Chem Regents Review 12190821

Which statement describes the earliest model of the atom?

• An atom is an indivisible hard sphere.

• An atom has a small, dense nucleus.

• Electrons are negative particles in an atom.

• Electrons in an atom have wave-like properties.

In all atoms of bismuth, the number of electrons must equal the

• number of protons

• number of neutrons

• sum of the number of neutrons and protons

• difference between the number of neutrons and protons

Which symbol represents a particle that has a mass approximately equal to the mass of a neutron?

• α

• β+

• β−

• p

An orbital is a region in an atom where there is a high probability of finding

• an alpha particle

• an electron

• a neutron

• a positron

Which electron shell in an atom of calcium in the ground state has an electron with the greatest amount of energy?

• 1

• 2

• 3

• 4

As the elements in Period 2 are considered in order from lithium to fluorine, there is an increase in the

• atomic radius

• electronegativity

• number of electron shells

• number of electrons in the first shell

Which element is classified as a metalloid?

• boron

• potassium

• sulfur

• xenon

Strontium and barium have similar chemical properties because atoms of these elements have the same number of

• protons

• neutrons

• electron shells

• valence electrons

Which term represents the fixed proportion of elements in a compound?

• atomic mass

• molar mass

• chemical formula

• density formula

Which two terms represent types of chemical formulas?

• mechanical and structural

• mechanical and thermal

• molecular and structural

• molecular and thermal