Periodic Table and Trends

Question 1

Effective Nuclear Charge (ENC)

Answer 1

electrons are attracted to the positevly charged nucleus and reppled by other electrons. Outer electrons experience both attraction to nucleus and repulsion from inner electrons. ENC increases atomic radius.

Question 2

Shielding

Answer 2

the repulsive force exerted on valance electrons by core electrons. This increases the atomic radius. The more core electrons the greater the shielding effect.

Question 3

Ionization Energy

Answer 3

the amount of energy required to remove an electron from an atom. Electrons may be removed successively; therefore, an element may have multiple IE’s.

Question 4

First Ionization Energy

Answer 4

the amount of energy needed to completely remove an electron from a neutral atom when it’s a gas. An atom with a low first ionization energy will become an ion easily.

Question 5

ENC Trends

Answer 5

increases across a period (left to right) as shielding is constant but protons increase with atomic number. Decreases down a group as increased sheilding outweighs the increase in atomic number

Question 6

Shielding Trends

Answer 6

increases down a group as electrons is added to new energy levels. Remains constant across a period as electrons are added to the same shell.

Question 7

Ionization Energy Trends

Answer 7

increases across a period (left to right) as number of protons increase meaning higher ENC, with constant shielding meaning electrons are pulled to the nucleus more making them harder to remove. Decreases down a group as shielding increases pushing electron further away from the nucleus making them easy to remove.

Question 8

Atomic Radius Trends

Answer 8

decrease across a period (left to right) as shielding is constant but ENC increases. Increases down a group as shielding increases, reducing ENC.