Periodic Trends

Question 1

Cation

Answer 1

a positively charged ion

ex: H+

Question 2

Anion

Answer 2

a negatively charged ion

ex: H-

Question 3

Atomic Radii

Answer 3

the distance from the nucleus to the outermost electrons of an atom

Question 4

Atomic Radii DECREASE across a PERIOD because . . .

Answer 4

there are more protons being added to the nucleus, which creates greater attraction to the electrons in each energy level, ultimately pulling the electrons closer to the nucleus making the atom smaller.

Question 5

Atomic Radii INCREASE across a GROUP because . . .

Answer 5

the outer shells of each atom increase and an atom with more outer shells means electrons are held less tightly (shielding) –> further away from the nucleus

Question 6

Electronegativity

Answer 6

measures how strongly an atom desires an electron

Question 7

Electronegativity INCREASES across a PERIOD because

Answer 7

as the number of electrons increase, the more electrons are wanted in order to reach stability (8 electrons)

Question 8

Electronegativity DECREASES down a GROUP because

Answer 8

there are more electrons being added (causing shielding) which causes the attraction between the nucleus and the electrons to decrease–> this makes it easy for the atom to give away an electron

Question 9

Ionization Energy

Answer 9

energy required to remove an electron from an atom

Question 10

Ionization Energy INCREASES across a PERIOD because

Answer 10

as you move across a period, atomic radius decreases –> outer electrons are therefore closer to the nucleus and are more strongly attracted to the center: DIFFICULT TO REMOVE OUTERMOST ELECTRON

Question 11

Ionization Energy DECREASES down a GROUP because

Answer 11

the electrons are further away from the nucleus (shielding) and are either to remove