Chem Jan 2025 MC

The subatomic particles in the nucleus of an oxygen atom include

• electrons, only

• neutrons, only

• protons and neutrons

• protons and electrons

Which phrase describes the charges and numbers of protons and electrons in an atom?

• have opposite charges and are equal in number

• have opposite charges and are unequal in number

• have the same charge and are equal in number

• have the same charge and are unequal in number

In the wave-mechanical model, which term identifies a region in an atom of lithium that is the most probable location of electrons in the ground state?

• hard sphere

• polar bond

• orbital

• spectrum

An atom of C-12 in the ground state and an atom of C-13 in the ground state are defined as isotopes of carbon because these atoms have the same number of protons and

• the same number of neutrons

• the same number of electron shells

• a different number of neutrons

• a different number of electron shells

At STP, which property can be used to differentiate between a 2.0-gram sample of oxygen, O₂(g), and a 2.0-gram sample of helium, He(g)?

• mass

• temperature

• reaction with sodium

• phase of each sample

How do the molecular structures and properties of oxygen, O₂, and ozone, O₃, compare?

• They have different molecular structures and the same properties.

• They have different molecular structures and different properties.

• They have the same molecular structure and the same properties.

• They have the same molecular structure and different properties.

Which substance can be broken down by chemical means?

• aluminum

• ammonia

• argon

• arsenic

Which type of bonding is present in a sample of zinc at STP?

• covalent bonding

• hydrogen bonding

• ionic bonding

• metallic bonding

Which formula represents a nonpolar molecule?

• CH₄

• HCl

• H₂O

• NH₃

Given the equation representing a reaction: F + F → F₂ What occurs during this reaction?

• Energy is absorbed as a bond is formed.

• Energy is released as a bond is formed.

• Energy is absorbed as a bond is broken.

• Energy is released as a bond is broken.