What is the symbol for helium?

What does the atomic mass(weight) number represent?

What does the atomic number represent?

If I know how many protons an atom has I also know how many _______ the atom has.

How many electrons fit on the first orbit (ring)?

the smallest particle of an element that can exist.

a pure chemical substance that cannot be physically split into a more simple substance. Each is made of one type of atom. Carbon, mercury and hydrogen are examples.

the smallest particle of a substance that can exist. It is composed of two or more atoms.

a substance made of atoms from two or more different elements.

a particle of matter that has a positive electrical charge and forms part of the nucleus of an atom.

a particle of matter that has no electrical charge and forms part of the nucleus of an atom.

a particle of matter that has a negative electrical charge and travels around the nucleus of an atom.

Number of protons. Top number in the element box.

Number of protons plus neutrons. Bottom number in the element box.

Tiny number to the right of the element symbol. Tells you how many atoms of that element.

A one or two letter representation of an element.

Protons and _____ are always the same amount.