Atom

The atomic mass unit is defined as:

• the mass of the hydrogen atom containing only one proton.

• the mass of electrons found in a carbon atom containing six protons and neutrons.

• 1/12 the mass of a carbon atom containing six protons and six neutrons.

• 1/14 the mass of a nitrogen atom containing 7 protons and 7 neutrons.

• none of the above

How many protons does Potassium (K) have?

• 19

• 39

• 20

• 58

• 18

All of the positive charge of an atom is concentrated in the nucleus.

• True

• False

The atom is the fundamental building block of everything we hear, feel, see, and experience.

• True

• False

The nucleus of an atom is a very small, dense region that contains over 99.9% of the atomic mass.

• True

• False

The mass of a proton is exactly the same as the mass of a neutron.

• True

• False

The charges on electrons and neutrons cancel each other to give neutral atoms.

• True

• False

An atom containing 8 protons, 9 neutrons, and 8 electrons would be considered charge-neutral.

• True

• False

The number of protons in an atom's nucleus defines the element.

• True

• False

If two atoms each contain different numbers of protons, the atoms must be from different elements.

• True

• False