Unit 3: Periodicity

Question 1

Properties of Metal

Answer 1

• usually a solid @ room temp (except Hg)
• shiny/lustrous
• malleable: can be hammered into sheets
• good conductors of heat + electricity
• high m.p.
• ductile: can be drawn into wires
• lose e-
• low values for electronegativity, ionization energy, and electron affinity values

Question 2

Properties of Nonmetals

Answer 2

• dull/lack luster
• poor conductor
  -insulator of heat + electricity
• gain e-
• high values for electronegativity, ionization energy, and electron affinity values

Question 3

Properties of Metalloids

Answer 3

• Have characteristics of both metals & nonmetals
• Physical properties/ appearance resemble metals
• Chemical properties resemble nonmetals

Question 4

Periods

Answer 4

Horizontal Rows (1-7)

Question 5

Groups

Answer 5

Vertical columns (1-18)
- sometime groups 3-12 are “omitted” and we call the remaining groups, Groups 1A-8A

Question 6

Group 1

Answer 6

Alkali metals

Question 7

Groups 3-12

Answer 7

Transition metals (d-block)

Question 8

Group 17

Answer 8

Halogens

Question 9

Group 18

Answer 9

Noble gasses

Question 10

Elements 58-71

Answer 10

Lanthanoids (f-block)

Question 11

Elements 90-103

Answer 11

Actinoids (f-block)

Question 12

Atomic Radius (group-trend)

Answer 12

As you move down a group, atomic radius increases
(“snowman effect”

Question 13

Why does atomic radius increase as you move down a group?

Answer 13

As the # of occupied energy levels increases, so does the size of the atom

Question 14

Atomic Radius (period-trend)

Answer 14

As you move across a period, atomic radius decreases

Question 15

Why does the atomic radius decrease as you move across a period?

Answer 15

Same: e- are being added to the same energy level
Different: the # of protons increases so the attraction between the increasingly positive center and (-) e- increases. This attraction “pulls in” the outer e-

Question 16

Ionic Radius (Cations) (Group)

Answer 16

Cations increase in size down a group as the outer energy level gets further from the nucleus (less attraction)

Question 17

Ionic Radius (Cations) (Period)

Answer 17

Cations in a period contain the same # of e- but an increasing # of protons, creasing the attraction between the (+) center and the (-) e-. thus decreasing the radius

Question 18

Ionic Radius (Anions) (Group)

Answer 18

Anions increase in size down a group as the outer energy level gets further from the nucleus (less attraction)

Question 19

Ionic Radius (Anions) (Period)

Answer 19

Anions in a period contain the same # of e- but an increasing # of protons, increasing the attraction between the (=) center and the (-) e-, thus decreasing the radis

Question 20

First Ionization Energy (definition)

Answer 20

The energy required to remove one electron from an atom in its gaseous state

Question 21

Ionization Energy (Group) (Trend)

Answer 21

As you move down a group, ionization energy decreases

Question 22

Why does the first ionization energy decrease as you move down a group?

Answer 22

The # of occupied energy levels increases, so the increased distance between the e- and the nucleus reduces the attraction (lower I.E. makes it easier to remove e-)

Question 23

Ionization Energy (Period) (Trend)

Answer 23

As you move across a period, ionization energy increases

Question 24

Why does the first ionization energy increase as you move across a period?

Answer 24

The extra e- are filling the same energy level, but the extra protons in the nucleus attract the energy level close making it harder to remove an e- (increasing I.E.)

Question 25

Electronegativity (definition)

Answer 25

A measure the ability to attract electrons in a covalent bond

Question 26

Electronegativity (Group) (Trend)

Answer 26

As you move down a group, electronegativity decreases

Question 27

Why does electronegativity decrease as you move down a group?

Answer 27

The bonding e- (outermost e-) are getting father from the nucleus and so there is reduced attraction

Question 28

Electronegativity (Period) (Trend)

Answer 28

As you move across a period electronegativity increases

Question 29

Why does electronegativity increase as you move across a period?

Answer 29

There is an increase in # of protons, resulting in an increased attraction between the nucleus and the bounding e-

Question 30

Electronegativity (Noble gasses)

Answer 30

no values no desire to attract an e-

Question 31

Electron Affinity (definition)

Answer 31

The energy change when an electron is added to an isolated atom in the gaseous state

Question 32

Metalloids

Answer 32

B, Si, Ge, As, Sb, Te, Po

Question 33

Melting Point

Answer 33

depends on the structure of the element and the type of attractive forces which hold the atoms together

Question 34

Melting Point (Metals)

Answer 34

exhibit metallic bounding (ex. Na, Mg, Al) which increase in strength as the # of valence e- increases

Question 35

Melting Point (Silicon)

Answer 35

The metalloid has a "unique" covalent structure with very strong bonds resulting in high m.p.

Question 36

Melting Point (Nonmetals)

Answer 36

P, S, Cl have a simpler molecuar structures with weak forces of attractions

Question 37

Melting Point (Ar/noble gasses)

Answer 37

exist as monatomic molecules (single atoms) with extremely weak forces of attraction between the atoms

Question 38

Melting Point (Group 1)

Answer 38

m.p. decreases down the group as the atoms become larger and the strength of the metallic bond decreases

Question 39

Melting Point (Group 17)

Answer 39

Halogens are held together by London dispersion forces. These get stronger as the number of electrons in the molecule increases

Question 40

Alkali metals

Answer 40

- very reactive metals - readily lose e- (low I.E.) -Chemical reactivity increases as you go down the group since less E is required to remove the e-, aiding in a faster/more vigorous reaction

Question 41

Halogens

Answer 41

- very reactive non-metals - Exist as diatomic molecules - react by gaining an e- - Reactivity decreases as you go down the group as the outer shell gets further from the nucleus, decreasing the attraction for another e-

Question 42

Most reactive metal

Answer 42

Francium

Question 43

Most reactive nonmetal

Answer 43

Fluorine

Question 44

Acid

Answer 44

- starts w/ H - lots of H+ (0-7)

Question 45

Basic

Answer 45

- end w/ OH - lots of OH- (hydroxide) (pH>7)

Question 46

Period 3

Answer 46

basic-> amphoteric -> acidic