Which subatomic particles were discovered as the result of experiments with cathode ray tubes?

• electrons

• neutrons

• positrons

• protons

Which numerical setup can be used to calculate the atomic mass of the element copper?

• (62.93 u)(30.85) + (64.93 u)(69.15)

• (62.93 u)(69.15) + (64.93 u)(30.85)

• (62.93 u)(0.3085) + (64.93 u)(0.6915)

• (62.93 u)(0.6915) + (64.93 u)(0.3085)

Which statement describes two different isotopes of carbon?

• The isotopes contain the same number of neutrons and have the same atomic number.

• The isotopes contain the same number of neutrons but have a different atomic number.

• The isotopes contain a different number of neutrons but have the same atomic number.

• The isotopes contain a different number of neutrons and have a different atomic number.

Diagram 1 represents an atom of hydrogen, showing the nucleus and the electron in the first shell. What is represented by diagram 2?

• a positive ion of hydrogen

• a negative ion of hydrogen

• an atom of hydrogen in an excited state

• an atom of hydrogen in the ground state

Which change in electron location in an atom of calcium is accompanied by the greatest amount of energy emitted?

• from shell 1 to shell 2

• from shell 2 to shell 1

• from shell 1 to shell 4

• from shell 4 to shell 1

The wave-mechanical model of the atom describes the location of electrons

• as loosely packed in the nucleus of an atom

• as densely packed in the nucleus of an atom

• in circular paths around the nucleus

• in orbitals outside the nucleus

Which atom forms an ion with a radius larger than the atomic radius?

• calcium atom

• oxygen atom

• lead atom

• tin atom

As the atomic number increases in Group 2 from Be to Ba, the first ionization energy

• decreases, and the atomic radius decreases

• decreases, and the atomic radius increases

• increases, and the atomic radius decreases

• increases, and the atomic radius increases

Tags

NGSS.HS-PS1-1

Which sample can be classified as a substance?

• air

• argon

• soil

• seawater

What is the number of moles in a 78.8-gram sample of MgCO₃ (gram-formula mass = 84.3 g/mol)?

• 0.949 mol

• 0.935 mol

• 0.843 mol

• 1.070 mol