Most of the mass of an atom is due to:

Chadwick discovered:

____________ placed protons and electrons together inside the nucleus.

A ________ is the amount of energy required to move an electron from one level to another.

The modern day model of the atom is called:

The SI unit for frequency is:

What is the electron configuration for Cu?

What is the electron configuration for Ca?

What is the electron configuration for Br?

A row of elements in the Periodic Table is called a:

Most of the elements in the Periodic Table are:

Group 17 is also known as The____________:

Group 2 is also known as the:

A(n) __________ is the particle of light that an atom emit when transitioning from an excited to a ground state.