Practice Regents #1 (126)

Which conclusion resulted directly from the gold foil experiment?

• Atoms are hard, indivisible spheres.

• Electrons in an atom are negatively charged.

• Atoms contain a small, dense nucleus.

• Electrons in an atom are in shells that have different energies.

Tags

NGSS.HS-PS1-8

What is the number of electrons in an atom with 37 protons and 49 neutrons?

• 12

• 37

• 49

• 86

Tags

NGSS.MS-PS1-1

Which statement describes the mass of an electron?

• An electron has the same mass as a proton.

• An electron has the same mass as a neutron.

• An electron has much less mass than a proton.

• An electron has much more mass than a neutron.

In the wave-mechanical model of the atom, electrons are located in regions called

• spectra

• orbitals

• quanta

• nuclei

At STP, a sample of potassium can be differentiated from a sample of rubidium based on

• density

• phase

• temperature

• pressure

Which statement describes a chemical property of chlorine?

• Chlorine has an atomic radius of 100. pm.

• Chlorine reacts with sodium to form a salt.

• Chlorine has a melting point of 172 K.

• Chlorine is a green-yellow gas at STP.

Tags

NGSS.HS-PS1-1

Oxygen gas, O₂ (g), and ozone gas, O₃ (g), are two forms of the element oxygen. These two forms of oxygen have

• the same molecular structures and the same properties

• the same molecular structures and different properties

• different molecular structures and the same properties

• different molecular structures and different properties

Tags

NGSS.MS-PS1-1

Which phrase describes two or more elements chemically combined?

• a mixture with a fixed proportion of elements

• a mixture with variable proportions of elements

• a compound with a fixed proportion of elements

• a compound with variable proportions of elements

Which formula is an empirical formula?

• N₂O₄

• N₂O₅

• N₂F₂

• N₂H₄

Which terms represent two different categories of compounds?

• covalent and molecular

• covalent and electrical

• ionic and molecular

• ionic and electrical