C02.6 Periodic Trends 1 Lecture

solids

protons

full of subatomic particles

electron cloud (empty space)

larger charges = stronger force

smaller charges = stronger force

greater separation = weaker force

greater separation = stronger force

266 pm

133 pm

266 Å

133 Å

periods

groups

Carbon

Nitrogen

Germanium

Silicon

can't tell from using just the periodic trend

Magnesium

Barium

can't tell from using just the periodic trend

Aluminum

Germanium

can't tell from using just the periodic trend

each step down adds another electron shell

a decrease in Z_eff causes the electron cloud to spread out

an increase in shielding electrons increases the force of attraction

Br

Br ^–

Na

Na⁺

the atoms have more mass, which increases the gravitational pull

it doesn't, atoms get bigger going from left to right because of the additional protons and electrons that are being added.

effective nuclear charge tends to increase

atoms lose energy levels make them smaller

Alkali metals

Halogens

Noble Gases

Transition metals

200 pm

100 pm

50 pm

25 pm

It increases the force of attraction between the protons thus pulling the protons closer together and making the atom smaller

It increases the force of attraction on the valence electrons thus pulling the electrons closer to the nucleus and making the atom smaller

If reduces the number of main energy levels or shells thus making the atom smaller

It increases the force of repulsion the electrons have on each other thus causing the electrons to spread out and making the atom smaller

Na⁺

Mg²⁺

Al³⁺

Sr²⁺

positive ion of strontium

Sr

neutral atom of strontium

ionization energy

electron affinity

electronegativity

atomic radius