Chemistry Midterm 24-25

Which description of the atom is based on the results of the gold foil experiment in the early 1900s?

• Atoms are small, dense, indivisible spheres.

• Atoms are composed of protons, electrons, and neutrons.

• Atoms have small, dense, positively charged nuclei.

• Atoms have electrons with wavelike properties.

Tags

NGSS.HS-PS1-8

According to the electron cloud model, which term is defined as the most probable location of an electron in an atom?

• configuration

• nucleus

• orbital

• spectrum

Which change occurs when an electron returns from a higher energy state to a lower energy state?

• An ionic compound is formed, and energy is emitted.

• An ionic compound is formed, and energy is absorbed.

• A specific amount of energy is absorbed.

• A specific amount of energy is emitted.

Tags

NGSS.HS-PS1-2

Which phrase describes the different isotopes of an element?

• same number of electrons and a different number of protons

• same number of protons and a different number of electrons

• same number of protons and a different number of neutrons

• same number of neutrons and a different number of protons

Which statement describes a chemical property of sodium?

• It is silver in color.

• It has a density of 0.97 g/cm³ at room temperature.

• It has atoms with an atomic radius of 160 pm.

• It is highly reactive with water.

Oxygen can exist as diatomic oxygen gas, O₂(g), or ozone, O₃(g). These two forms of oxygen have

• the same molecular structure and the same properties

• different molecular structures and different properties

• the same molecular structure and different properties

• different molecular structures and the same properties

Tags

NGSS.MS-PS1-1

Which formula contains a polyatomic ion?

• KCN

• K₂S

• AlBr₃

• Al₂O₃

Which quantity is conserved in all chemical reactions?

• charge

• density

• moles

• volume

Tags

NGSS.HS-PS1-7

At STP, which substance has metallic bonding?

• argon

• barium chloride

• sulfur dioxide

• titanium

How many pairs of electrons are shared between the nitrogen atoms in a molecule of N₂?

• 1

• 2

• 3

• 4