2. Atoms & Elements

Where are protons and neutrons found within an atom?

An atom's atomic number is 7. Its valence is most likely:

How many protons are present in the nucleus of a standard hydrogen atom?

The reactivity of an atom arises from:

The smallest units of matter that retain the chemical properties of an element are called:

Which of the following correctly describes the number of protons, neutrons, and electrons in a neutral atom of barium-137 (Ba-137)?

How many oxygen atoms are present in a single molecule of water (H_2O)?

In an atom, where are the electrons primarily located?

The atomic number of magnesium is 12. This means that its nucleus must contain:

What is the number of protons in a neutral carbon atom?

Which statement correctly describes the difference in electric charge between protons and electrons in an atom?

A scientist wants to create a plasma in the laboratory. Which of the following methods can be used to make a plasma?

Which of the following best describes the smallest particle of an element that can exist?

Which of the following best describes the fundamental composition of matter?

An atom with its first two electron shells completely filled would contain how many electrons?