Moving left to right across a period on the periodic table, atomic radius decreases due to a stronger nuclear pull on electrons, while atomic mass increases because of the addition of protons and neutrons.
Two key factors affecting these trends include the increase of the atomic number (Z) and the effective nuclear charge felt by valence electrons. As a result, several trends can be observed：
Reactivity does not uniformly increase; it typically decreases for metals and increases for nonmetals.
Atomic radius decreases due to the increasing effective nuclear charge.
Atomic mass increases because elements have more protons, neutrons, and electrons.
Valence electrons generally increase, not decrease, as we add more electrons to fill the outermost shell.
When considering the provided trends, atomic radius decreasing and atomic mass increasing are trends that accurately describe what happens when moving left to right across a period. The atomic radius decreases mainly because a greater nuclear charge exerts a stronger pull on the electrons, drawing them closer to the nucleus. As the atomic mass increases, this is because protons and neutrons are being added to the nucleus as you move across the period. While reactivity varies depending on the type of elements (metals or nonmetals), we know that valence electrons actually increase as we move across a period, which is contrary to one of the listed answer choices.
2)
____________________ helps explain why there are a large number of marsupial mammal species in Australia and South America, two continents that were once connected.
A) Ozone production
B) Continental drift
C) The fifth mass extinction
Eliminate
D) The first mass extinction
What is the outermost layer of the earth?
_____ is a control mechanism that intensifies an earlier reaction. A sensory receptor An effector Negative feedback Positive feedback
The sensory receptors are nerve endings or specialized cells able to capture internal or external stimuli, and generate in response nerve impulses.
The answer is: A sensory receptor.
An organism that contains chloroplasts is able to produce food by the process of
Scientist call an organism that has two different alleles for a trait
What kind of bond holds together atoms within a molecule?
The bond holds together atoms within a molecule is ionic bonds, covalent bonds and metallic bonds.
There are three main types of chemical bonds that hold atoms together within a molecule:
1. Ionic bonds are formed when one atom donates electrons to another atom. The atom that donates electrons becomes a positively charged ion, and the atom that receives electrons becomes a negatively charged ion. The oppositely charged ions are attracted to each other by the electrostatic force.
2. Covalent bonds are formed when two atoms share electrons. The shared electrons are attracted to the nuclei of both atoms, which holds the atoms together. Covalent bonds can be either polar or nonpolar. Polar covalent bonds occur when the atoms share the electrons unequally, while nonpolar covalent bonds occur when the atoms share the electrons equally.
3. Metallic bonds are formed when metal atoms share their valence electrons with each other. The valence electrons form a "sea" of electrons that surrounds the metal atoms. The metal atoms are attracted to the sea of electrons, which holds the atoms together.
The type of bond that holds atoms together in a molecule depends on the elements that make up the molecule and the electronegativity of the atoms. Electronegativity is a measure of how strongly an atom attracts electrons. Atoms with high electronegativity tend to form ionic bonds, while atoms with low electronegativity tend to form covalent bonds.
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Why is charcoal a limited drawing medium?
Ammonia is _____.
an acid
a base
a neutral
Ammonia is a base! Have a blessed day!
-Steel jelly
In a machine shop, two cams are produced, one of aluminum and one of iron. Both cams have the same mass. Which cam is larger? (a) the aluminum cam (b) the iron cam (c) Both cams have the same size. ...?
Answer:
A - The aluminum can
Explanation:
Aluminum has a lower density than Iron does.
Imagine having a beachball sized ball of both aluminum and iron... The aluminum ball would be nice and light but that iron ball would definitely crush your toes if you dropped it on your foot! Even if they're the same exact size, they have totally different weights.
What is the difference between a molecule and a compound?
Selenium has six valence electrons. What is the valence of selenium?
Answer:
Two electrons because you need 8 electrons to make a atom stable and selenium has 6 electrons.
Explanation:
The valence of selenium, typically -2, refers to its combining power based on its six valence electrons with the configuration 4s²4p⁴. In compounds, selenium tends to gain two electrons to fill its valence shell.
Explanation:The valence of selenium is the combining power of an element, especially as measured by the number of hydrogen atoms it can displace or combine with.
Selenium has six valence electrons, as indicated by its valence electron configuration: 4s²4p⁴. This means in the fourth energy level (n = 4 shell), selenium has a total of six electrons that can interact with other atoms to form chemical bonds. The valence of selenium can vary depending on the type of compound it forms; however, it is typically -2, as it often seeks to gain two electrons to fill its valence shell and achieve a stable noble gas configuration.
how many sigma and pi bonds are there in phenol?
Phenol rocks 9 sigma (6 C-H, C-O, 2 O-H) and 3 pi bonds (1 C=O, 3 benzene ring).
There are 9 sigma bonds and 3 pi bonds in a phenol molecule.
Here's the step-by-step breakdown:
1. Sigma bonds:
Each single bond between carbon and hydrogen atoms is a sigma bond. There are 6 C-H bonds in the benzene ring, so there are 6 sigma bonds from these.There is one C-O single bond between the benzene ring and the hydroxyl group. This contributes another sigma bond.The O-H bond in the hydroxyl group is also a sigma bond.2. Pi bonds:
The double bond between the carbon and oxygen atoms in the hydroxyl group consists of one sigma bond and one pi bond. So, there is one pi bond here.The benzene ring has a special delocalized structure with alternating single and double bonds. However, each of these bonds still involves one sigma bond and one pi bond. There are 3 double bonds in the benzene ring, so there are 3 pi bonds from these.Therefore, in total, there are 9 sigma bonds (6 from C-H, 1 from C-O, 2 from O-H) and 3 pi bonds (1 from C=O, 3 from benzene ring) in a phenol molecule.
The complete question is here:
How many sigma and pi bonds are there in phenol?
How does the absorption of ultraviolet radiation by the ozone layer help sustain life? a. This process helps maintain the temperature of the Earth. b. It keeps a low level of harmful ultraviolet radiation from reaching living organisms. c. This process keeps ozone concentrations in the troposphere at lower levels. d. All of the above are true.
Answer: d. All of the above are true.
Explanation: Ozone is a protective shield present in earth's stratosphere which absorbs the harmful radiations from the sun and thus keeps a low level of harmful ultraviolet radiation from reaching living organisms.
As the sun rays are absorbed by the ozone layer, not all the sun rays reach the earth's surface and thus the temperature of the earth is also maintained.
The ozone present in the troposphere also called as ground level ozone is harmful as it can trigger a variety of health problems and is formed by reactions of pollutants from vehicular emissions in the presence of sunlight. Thus ozone in stratosphere blocks the sunlight and thus prevents the formation of ground level ozone.
Thus all the statements are true.
Which is true about batteries?
A. They all contain graphite rods and zinc electrodes.
B. They all contain parallel cells that increase energy output.
C. They always contain different cells that work together to produce energy.
D.They often have identical cells in series to increase energy output
Answer:
D.They often have identical cells in series to increase energy output
Explanation:
lol i stg thats the answer just took quiz on edge
Which of the following characteristics of carbon is responsible for the variety of carbon-based molecules on Earth?
A) It can form bonds.
B) It can form proteins.
C) It has four valence electrons.
D) It is organic in nature.
...?
which solution has a molality of 0.25m NaCl?
I WIll upvote for answer
Balance the following reaction Fe^2 O ^3 +HCI+FeCI^3+H^2O
How many total atoms are in 0.240 g of P2O5?
To calculate the total number of atoms in 0.240 g of P2O5, you need to convert the mass to moles and then use Avogadro's number to find the total number of atoms.
Explanation:To determine the total number of atoms in 0.240 g of P2O5, you first need to calculate the number of moles of P2O5 using its molar mass. The molar mass of P2O5 is 141.9446 g/mol. You can use the formula: moles = mass / molar mass. Plugging in the values gives: moles = 0.240 g / 141.9446 g/mol = 0.00169 mol.
Next, use Avogadro's number (6.022 x 10^23 atoms/mol) to calculate the total number of atoms. Multiply the number of moles by Avogadro's number:
total atoms = 0.00169 mol x 6.022 x 10^23 atoms/mol = 1.02 x 10^21 atoms.
To fulfill the octet rule electron sharing leads to ____ electrons around each atom?
A. 4
B. 5
C. 6
D. 8
4NH3 + 5O2 4NO +6H2O
In an experiment, 3.25 g of NH3 are allowed to react with 3.50 g of O2. How many grams of NO are formed?
Please round final answers to the tenth position, one place after the decimal
[tex]\boxed{2.6264752{\text{ g}}}[/tex] of NO is formed during the given reaction.
Further explanation:
Limiting reagent is the species or reagent in a chemical reaction according to which the amount of product is decided. It is completely consumed in the reaction.
Stoichiometry governs the amount of species present in the reaction by using the relationship between reactants and products.
The given reaction is as follows:
[tex]{\text{4N}}{{\text{H}}_3} + {\text{5}}{{\text{O}}_2} \to {\text{4NO}} + 6{{\text{H}}_{\text{2}}}{\text{O}}[/tex]
The formula to calculate the moles of the substance is as follows:
[tex]{\text{Moles of substance}} = \dfrac{{{\text{Given mass of substance}}}}{{{\text{Molar mass of substance}}}}[/tex] ...... (1)
Substitute 3.25 g for the given mass and 17.03 g/mol for the molar mass in equation (1) to calculate the moles of [tex]\text{NH}_3[/tex].
[tex]\begin{aligned}{\text{Moles of N}}{{\text{H}}_3} &= \left( {\frac{{{\text{3}}{\text{.25 g}}}}{{17.03{\text{ g/mol}}}}} \right)\\&= 0.1908{\text{ mol}}\\\end{aligned}[/tex]
Substitute 3.50 g for the given mass and 31.98 g/mol for the molar mass in equation (1) to calculate the moles of [tex]\text{O}_2[/tex].
[tex]\begin{aligned}{\text{Moles of }}{{\text{O}}_2} &= \left( {\frac{{{\text{3}}{\text{.50 g}}}}{{{\text{31}}{\text{.98 g/mol}}}}} \right)\\&= 0.1094{\text{ mol}}\\\end{aligned}[/tex]
According to the stoichiometry of this reaction, four moles of reacts with five moles of [tex]\text{O}_2[/tex] to form four moles of NO and six moles of [tex]\text{H}_2\text{O}[/tex].
Calculate the moles of [tex]\text{O}_2[/tex] that react with and 0.1908 moles of [tex]\text{NH}_3[/tex] as follows:
[tex]\begin{aligned}{\text{Amount of }}{{\text{O}}_2} &= \left( {{\text{0}}{\text{.1908 mol N}}{{\text{H}}_3}} \right)\left( {\frac{{{\text{5 mol }}{{\text{O}}_2}}}{{4{\text{ mol N}}{{\text{H}}_3}}}} \right)\\&= 0.2385{\text{ mol }}{{\text{O}}_2}\\\end{aligned}[/tex]
The above calculations concluded that 0.2385 moles of [tex]\text{O}_2[/tex] are needed to react with 0.1908 moles of [tex]\text{NH}_3[/tex] but only 0.1094 moles of [tex]\text{O}_2[/tex] are present in the reaction mixture. Therefore, [tex]\text{O}_2[/tex] is present in limited quantity and is a limiting reagent.
Since [tex]\text{O}_2[/tex] comes out to be the limiting reagent, the formation of NO is governed by it. According to the reaction stoichiometry, five moles of [tex]\text{O}_2[/tex] produces four moles of NO. Therefore the amount of NO can be calculated as follows:
[tex]\begin{aligned}{\text{Amount of NO}} &= \left( {0.1094{\text{ mol }}{{\text{O}}_2}} \right)\left( {\frac{{4{\text{ mol NO}}}}{{5{\text{ mol }}{{\text{O}}_2}}}} \right)\\&= 0.08752{\text{ mol}}\\\end{aligned}[/tex]
Rearrange equation (1) to calculate the mass of the substance.
[tex]{\text{Mass of substance}}= \left( {{\text{Moles of substance}}} \right)\left( {{\text{Molar mass of substance}}} \right)[/tex] ...... (2)
Substitute 0.08752 mol for the moles and 30.01 g/mol for the molar mass in equation (2) to calculate the mass of NO.
[tex]\begin{aligned}{\text{Mass of NO}} &= \left( {0.08752{\text{ mol}}} \right)\left( {30.01{\text{ g/mol}}} \right)\\&= 2.6264752{\text{ g}}\\\end{aligned}[/tex]
Learn more:
Calculate the moles of chlorine in 8 moles of carbon tetrachloride: https://brainly.com/question/3064603 How many grams of potassium was in the fertilizer? https://brainly.com/question/5105904
Answer details:
Grade: Senior School
Chapter: Mole concept
Subject: Chemistry
Keywords: limiting reagent, NH3, NO, H2O, O2, 2.6264752 g, moles, mass, molar mass.
Why does hot air rise and cold air sink??
Explanation:
In hot air, molecules have more kinetic energy and due to this they move from one place to another. As a result, there occurs more number of collisions between the molecules. Due to this molecules of hot air tend to rise.
Whereas when air is cold then its molecules are closer to each other. As a result, they do not have enough kinetic energy and they do not move from their initial position.
Hence, cold air sinks because of lack of movement in its molecules.
Hot air is less denser than cold air, which is why hot air rises and cold air sinks.
The invisible gaseous cloud that envelops the Earth and reaches into space is called air. About 78% of it is nitrogen, 21% is oxygen, and the remaining 2% or so is made up of different contaminants, water vapour, carbon dioxide, and other trace gases.
Air molecules move more quickly when it warms near the surface of the Earth or on the first level of a building, producing more space between them and making the air less dense than the cooler air above it. Cooler, more dense air sinks while warmer, less dense air rises. Since cooler air's molecule bonds absorb less energy than hot air's, cooler air is denser and hence heavier.
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some small hybrid cars and sport utility vehicles also have spoilers.what is their purpose? Is it the same or different from the spoiler on a sports car?
Spoilers in small hybrid cars, SUVs, and sports cars aim to reduce lift and drag and improve the grip of the car on the road. They are crucial for sports cars due to the high speeds involved. However, small hybrid cars and SUVs, contribute more towards aesthetics and fuel efficiency, but the principle of operation remains the same.
Explanation:Spoilers are used in vehicles, including small hybrid cars and sport utility vehicles (SUVs), as well as sports cars, primarily to reduce lift and drag, and enhance the car's road grip. Generally, spoilers work on the principle of aerodynamics. For sports cars, in particular, the spoiler becomes more significant at high speeds, redirecting air flows to create a downward force that stabilizes the car, enhancing safety during high-speed maneuvers.
Although the purpose is fundamentally the same across all vehicles, the importance of spoilers may vary. In sports cars, with their high-speed indulgence, spoilers are essential components. On the other hand, for small hybrid cars and SUVs, brackets are used more for aesthetic appeal and fuel efficiency. However, the basic function of a spoiler in either scenario remains—to control airflow.
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Explain how line spectra are used to identify elements and what they indicate about atoms
Electron transitions from higher to lower energy levels cause emission of energy in the form of electromagnetic waves, each with their own specific wavelength. Because the energy levels of elements are quantized, each transition has a specific energy difference. The collection of these transitions makes up the emission spectrum and each spectrum is unique to a specific element, allowing identification.
Does elements in group 2 lend electrons
Yes, Group 2 elements, the alkaline earth metals, lose two electrons to form +2 ions, achieving a noble gas electron configuration, and are typically found as compounds due to their reactivity.
The elements in Group 2 of the periodic table are known as the alkaline earth metals. These elements, which include beryllium, magnesium, calcium, strontium, barium, and radium, have two electrons in their outermost energy level.
In chemical reactions, these Group 2 elements tend to lose two electrons to achieve a noble gas configuration, resulting in a +2 oxidation state. This is because they seek to have a full valence shell, similar to the nearest noble gas in the periodic table.
Group 17 elements (halogens) aim to gain one electron to complete their valence shells, while Group 14 elements have the ability to gain or lose four electrons depending on the context. Group 1 elements, also known as alkali metals, readily lose one electron in chemical reactions.
The chemical reactivity of alkaline earth metals is significant, but not as high as their Group 1 counterparts, due to the higher energy required to remove two electrons. Yet, they are reactive enough that they are not found free in nature, only in compound forms. The reactivity and the +2 oxidation state dominate the chemistry of Group 2 elements.
What is a renewable source of energy? a. An energy resource that is used up over time. b. An energy resource that is available and can be recreated. c. An energy resource that is no longer used. d. An energy resource that is now used more than oil and gas.
the equation A+X AX is the general equation for a(n)
Mexico City has an elevation of 7400 ft above sea level. Its normal atmospheric pressure is 589 mm Hg. At what temperature does water boil in Mexico City?
Final answer:
The boiling point of water in Mexico City, with an elevation of 7400 ft and an atmospheric pressure of 589 mm Hg, is lower than the sea level boiling point of 100°C. It would be approximately between 90°C and 95°C, although a nomogram or the Clausius-Clapeyron relation would be needed for a precise value.
Explanation:
At higher altitudes, such as Mexico City's elevation of 7400 ft, the atmospheric pressure is significantly lower than at sea level. This decreased pressure results in a lower boiling point of water. While the boiling point of water is 100°C at sea level (760 mm Hg), in Mexico City with an atmospheric pressure of 589 mm Hg, the boiling point is reduced. Based on Table 10.1.4, we can infer that as the altitude increases in places like Mexico City, the boiling point of water decreases. From Table 10.4.1, for example, we notice that at an elevation similar to Mexico City's, the boiling point can be several degrees lower than 100°C. Unfortunately, without the specific data for 589 mm Hg from these tables, we cannot give the exact boiling point temperature, but it would typically be between 90°C and 95°C.
To determine the exact boiling point at a specific altitude and pressure, such as Mexico City's, one would often use a nomogram or a formula derived from the Clausius-Clapeyron relation, which correlates temperature and pressure for the phase change between liquid and gas. To obtain a precise value for Mexico City, it is advisable to consult such a nomogram designed for this purpose.
Why are carbon compounds that contain mercury and a greater environment concern than elemental mercury? ...?
A scientist examining the periodic table sees that the element magnesium (Mg) has the atomic number of 12.
Based on this knowledge, what does the scientist immediately know is true about magnesium atoms?
Magnesium atoms have 12 protons.
Magnesium atoms have 6 protons and 6 electrons.
Magnesium atoms have 12 neutrons.
Magnesium atoms have 6 protons and 6 neutrons.
The answer should be Magnesium atoms have 12 protons. This is because the atomic number of an element indicates how many protons there are. Hope this helps someone down the road!
A gas of unknown identity diffuses at a rate of 83.3 mL/s in a diffusion apparatus in which carbon dioxide diffuses at the rate of 102 mL/s. Calculate the molecular mass of the unknown gas. Give your answers in units of g/mol to three significant figures.
Answer: 65.7 g/mol
Explanation:
To calculate the rate of diffusion of gas, we use Graham's Law.
This law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows:
[tex]\text{Rate of diffusion}\propto \frac{1}{\sqrt{\text{Molar mass of the gas}}}[/tex]
[tex]\frac{Rate_{X}}{Rate_{CO_2}}=\sqrt{\frac{M_{CO_2}}{M_{X}}}[/tex]
[tex]\frac{83.3}{102}=\sqrt{\frac{44}{M_{X}}[/tex]
Squaring both sides and solving for [tex]M_{X}[/tex]
[tex]M_{X}=65.7g/mol[/tex]
Hence, the molar mas of unknown gas is 65.7 g/mol.