chem unit 2 part 2

Question 1

how is the periodic table arranged and why?

Answer 1

increasing atomic number and a periodic repetition of physical and chemical properties

Question 2

why do elements in the same group have similar properties?

Answer 2

they have similar valance electron configurations. the properties of an element (physical properties, reactivity, etc.) are determined by the valance electron

Question 3

define valance electrons

Answer 3

electrons in the highest filled energy level or outermost shell of an atom

Question 4

what are the 3 main classes of elements?

Answer 4

metals, metalloids, and non metals

Question 5

what are the similarities between alkali metals and transition metals?

Answer 5

-metals
-malleable
-ductile
-tensile strength
-good conductors of heat and electricity

Question 6

what are differences between alkali metals and transition metals?

Answer 6

-alkali metals are highly reactive (especially with water) and they do not exist freely in nature
-transition metals are less reactive and exist freely in nature

Question 7

what are the similarities between lanthanides and actinides?

Answer 7

-heavy metals
-in the inner transition section of the periodic table

Question 8

what are the differences between lanthanides and actinides?

Answer 8

-lanthanides are “rare earth metals”
-actinides are mostly radioactive and synthetic/man-made

Question 9

define atomic radius

Answer 9

distance between the center of the nucleus of an atom and the edge of an atom
-decreases from left to right in a period
-increases down a group

Question 10

define ionization energy

Answer 10

energy required to remove an electron from an atom
-increases from left to right in a period
-decreases down a group

Question 11

define electronegativity

Answer 11

ability for an atom to attract electrons in a compound
-increases from left to right in a period
-decreases down a group

Question 12

why does electronegativity increases from left to right in a period?

Answer 12

protons in the nucleus attract electrons. as the number of protons in the nucleus increases, electronegativity or attraction increases

Question 13

why does electronegativity decrease down a group?

Answer 13

electrons are further away from the nucleus, so the nucleus doesn’t have as strong of a pull on the electrons

Question 14

why does atomic radius decrease from left to right in a period?

Answer 14

electrons with a greater nuclear charge (as atomic number increases) are held more closely to the nucleus

Question 15

why does atomic radius increase down a group?

Answer 15

as the electrons fill higher energy levels, the atomic radius increases because there are more shells

Question 16

why does ionization energy increase from left to right in a period?

Answer 16

moving across a period, electrons in the outer shell are held closer to the nucleus and require more energy to remove a negative charge

Question 17

why does ionization energy decrease down a group?

Answer 17

electrons are further away from the nucleus and are easier to remove

Question 18

what are columns on the periodic table called?

Answer 18

groups

Question 19

what are rows on the periodic table called?

Answer 19

periods

Question 20

the 7 periods on the periodic correspond to the _____ where electrons can exist in an atom

Answer 20

energy levels/shells

Question 21

what elements are metalloids?

Answer 21

B, Si, Ge, As, Sb, and Te

Question 22

where are transition metals located?

Answer 22

d block

Question 23

where are lanthanides located?

Answer 23

4f

Question 24

where are actinides located?

Answer 24

5f

Question 25

lanthanides

Answer 25

“rare earth metals”

Question 26

actinides

Answer 26

radioactive

Question 27

alkali metals

Answer 27

-group 1A
-extremely reactive (explosive with water)
-not found free in nature
-soft
-lustrous

Question 28

alkaline earth metals

Answer 28

-group 2A
-harder, denser, and stronger than alkali metals
-less reactive than alkali metals, but still too reactive to be found free in nature
-used in flares and fireworks

Question 29

halogens

Answer 29

-group 7A
-most reactive non-metals

Question 30

noble gases

Answer 30

-group 8A
-inert/non-reactive
-8 valance electrons

Question 31

transition metals

Answer 31

-good conductors of heat and electricity
-ductile
-malleable
-lustrous
-less reactive
-free elements
-d block

Question 32

for any representative element (in main groups 1A-8A), how can you easily determine the number of
valence electrons it has?

Answer 32

group number= number of valence electrons