Atoms & Atomic Structure Exp 1

The mass of an atom mostly depends on

The number of protons and neutrons in the nucleus

Why doesn’t atomic volume always increase as atomic mass increases?

Because atomic volume is determined by the electrons, not the nucleus. As nucleus increases, protons increase as well, causing the electrons to be pulled closer to the nucleus, making the atom smaller

How does atomic radius change across a period and down a group?

Across a period → decreases (more protons pull electrons closer)

Down a group → increases (more electrons shells are added even whilst protons are being added)

atoms get smaller as… (atomic radii)

As you go from left to right across a period

atoms get larger as you… (atomic radii)

Go down a group

Finding the volume of an atom

4/3 x pi x r³ (radius is always given)