The mass of a proton is approximately equal to the mass of*

An orbital of an atom is defined as the most probable location of*

What must occur when an electron in an atom returns from a higher energy state to a lower energy state?*

Which element is a liquid at 305 K and 1.0 atmosphere?*

Which list of elements consists of a metal, a metalloid, and a nonmetal?*

At STP, which physical property of aluminum always remains the same from sample to sample?*

Which statement describes a chemical property of silicon?*

Which diagram represents a mixture of two different molecular forms of the same element?

*

(1)

(2)

(3)

(4)

A compound is broken down by chemical means during*

Which quantities must be conserved in all chemical reactions?*

Which phrase describes the distribution of charge and the polarity of a CH₄ molecule?*

What is the charge of the nucleus of an oxygen atom?*

Which ion has no electrons?*

To break a chemical bond, energy must be*

Which Lewis electron-dot diagram represents a nitrogen atom in the ground state?*

(1)

(2)

(3)

(4)