Question

1. as an atom in the ground state changes to an atom in an excited state, the atom 1

a. absorbs energy
b. releases energy
c. increases in mass number
d. decreases in mass number

1. which statement describes a chemical property of copper? 1

a. copper has a red - orange color.
b. copper can be flattened into sheets.
c. copper reacts with oxygen.
d. copper conducts an electric current.

1. at stp, two forms of solid carbon, diamond and graphite, have different properties because 1

a. diamond has a different percent composition than graphite
b. diamond has more electrons per atom than graphite
c. diamond has stronger hydrogen bonding than graphite
d. diamond has a different crystal structure than graphite

1. which element in period 2 has the highest first ionization energy? 1

a. boron
b. lithium
c. neon
d. nitrogen

Explanation:

Question 45

An atom in the ground state has electrons in the lowest possible energy levels. To move to an excited state, electrons must move to higher energy levels, which requires absorbing energy. Mass number (protons + neutrons) doesn't change with energy state changes. So the atom absorbs energy.

Chemical properties involve how a substance reacts with other substances. Physical properties are about appearance, state, or physical changes. Color (a), being flattened (b, malleability), and conducting electricity (d) are physical properties. Reacting with oxygen (c) is a chemical property as it involves a reaction.

Diamond and graphite are allotropes of carbon, meaning they have the same elemental composition (so a is wrong) and same number of electrons per atom (b is wrong). Carbon doesn't form hydrogen bonds (c is wrong). Their different properties come from different crystal structures (arrangement of atoms), so d is correct.

Answer:

a. absorbs energy

Question 46