Atomic Structure and Periodic Trends

Sodium (Na)

Chlorine (Cl)

Aluminum (Al)

Magnesium (Mg)

It increases

It decreases

It remains constant

It first increases, then decreases

$$1s^2 2s^2 2p^6 3s^2 3p^6$$

$$1s^2 2s^2 2p^6 3s^2 3p^6 4s^2$$

$$1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$$

$$1s^2 2s^2 2p^6 3s^2 3p^5$$

Oxygen (O)

Potassium (K)

Calcium (Ca)

Sulfur (S)

They have a full outer electron shell

They have high electronegativity

They have low ionization energy

They have incomplete electron shells

Carbon-14

Nitrogen-14

Oxygen-16

Helium-4

:Cl:

:Cl: with 8 dots

:Cl: with 6 dots

:Cl: with 7 dots

Reactivity decreases

Reactivity increases

Reactivity remains constant

Reactivity first decreases, then increases

Fluorine has a higher atomic number

Fluorine has a smaller atomic radius

Fluorine has more protons

Fluorine has a lower electronegativity

Alkali metals

Halogens

Noble gases

Transition metals