Periodic Trends Lesson

potassium (K)

bromine (Br)

Aluminum (Al)

Chlorine (Cl)

Nitrogen (N)

Arsenic (As)

alkali metals

alkaline earth metals

halogens

noble gases

you add more and more neutrons

you add more and more protons

you add more and more shells (energy levels)

you add more atomic mass

Ar

He

Kr

Rn

the number of protons increases, so attraction to electrons increases

the number of energy levels increases

the number of electrons increases

the atomic mass increases

it has the smallest number of valence electrons

it has the greatest atomic mass

it has the greatest number of protons, so it attracts its electrons the strongest

its 1 valence electron is very far from the nucleus, so little energy is needed to remove it

Names

atomic numbers

atomic masses

properties

H

F