2. Atoms & Elements

Approximately how much of the air we breathe is composed of nitrogen and oxygen combined?

Which term best describes the total amount of protons, neutrons, and electrons that make up an object?

A copper penny has a net charge of -3.2 × 10^{-19} C. How many electrons were transferred to create this charge on the penny?

An atom has 23 protons and 29 neutrons. Which is the correct chemical symbol for this atom?

Which scientist is credited with the discovery of the proton?

Stars are made up mostly of which two elements?

Which of the following best describes the molecule represented as O2?

Which of the following electronic transitions within a hydrogen atom is not possible?

Why do neutrons not affect the charge of an atom?

Which of the following best describes an atom?

In a water molecule (H₂O), which atom has a slightly negative charge?

Which part of an atom is positively charged?

How many protons are present in a neutral atom of neon (Ne)?

Which statement is true with respect to an atom?

Electrons have which type of electrical charge?