Chapter 5

Question 1

What did Dobereiner do?

Answer 1

observed that elements could be classified into sets of three called TRIADS

Question 2

triads

Answer 2

a group of three elements with similar chemical properties

Question 3

What did Newlands do?

Answer 3

created the law of OCTAVES

Question 4

law of octaves

Answer 4

when elements are arranged in order of increasing atomic mass, the properties of the eighth element are similar to the properties of the first, the ninth like the second, etc

Question 5

What did Mendeleev do?

Answer 5

noticed that when elements were arranged in order of increasing atomic mass, certain similarities in their chemical properties appeared in regular intervals

Question 6

periodic

Answer 6

repeating patterns

Question 7

Why does Mendeleev get credit for the periodic table?

Answer 7

organized the table by grouping elements with similar properties, left a few spots blank, and accurately predicted the properties of these unknown elements

Question 8

What did Moseley do?

Answer 8

discovered elements fit into patterns better when they were arranged according to atomic number rather than atomic weight

Question 9

periodic law

Answer 9

physical and chemical properties of elements are periodic functions of their atomic numbers

Question 10

periodic table

Answer 10

arrangement of elements in order of their atomic numbers so that elements with similar properties fall in the same columns or groups

Question 11

elements arranged in groups

Answer 11

have similar chemical properties

Question 12

length of period

Answer 12

determined by number of electrons that can occupy the sublevels filled in that period

Question 13

blocks

Answer 13

s,p,d,f; determined by electron sublevel being filled in that block

Question 14

alkali metals

Answer 14

group 1 elements, most reactive metals, silvery appearance, soft

Question 15

alkaline earth metals

Answer 15

group 2 elements, less reactive than alkali but too reactive to find in nature in pure form

Question 16

Hydrogen

Answer 16

electron config of 1s^1 but does not share properties as group 1

Question 17

Helium

Answer 17

in group 18 because it’s nonreactive

Question 18

transition elements

Answer 18

d-block elements, typically metallic properties, 3 through 12

Question 19

p-block elements

Answer 19

groups 13 through 18, except for Helium

Question 20

main group elements

Answer 20

s and p block elements

Question 21

p block elements

Answer 21

right side is all nonmetals but Hydrogen and Helium, all six metalloids are in p block, left and bottom are eight p block metals

Question 22

p block element properties

Answer 22

vary greatly

Question 23

halogens

Answer 23

group 17, most reactive nonmetals, react with most metals to form compounds known as salts

Question 24

Flourine

Answer 24

most reactive nonmetal

Question 25

metalloids

Answer 25

semiconducting elements located between nonmetals and metals in p block

Question 26

p block metals

Answer 26

harder and denser than s block alkaline earth metals but softer and less dense than d block metals

Question 27

f block

Answer 27

wedged between groups 3 and 4 due to them filling 4f sublevel

Question 28

lanthanides

Answer 28

first row of f block, shiny metals similar in reactivity to group 2 alkaline earth metals

Question 29

periodic trend

Answer 29

property of an element that can be predicted from the arrangement in periodic table

Question 30

atomic radius

Answer 30

distance from center of atom’s nucleus to outermost electron

Question 31

How to increase atomic radius?

Answer 31

going right to left across period and down periods

Question 32

cation

Answer 32

atom loses electrons and becomes smaller, positive charge

Question 33

anion

Answer 33

atom gains electrons and becomes larger, negative charge

Question 34

Why does an atom get smaller when losing electrons?

Answer 34

losing electrons increases positive force which then pulls electrons closer to nucleus and reduces radius

Question 35

octet rule

Answer 35

atoms tend to gain, lose, or share electrons in order to acquire a full set of valence electrons

Question 36

octet

Answer 36

set of eight

Question 37

valence electrons

Answer 37

electrons on outermost energy level

Question 38

When are atoms stable?

Answer 38

when they have eight valence electrons

Question 39

ionization energy

Answer 39

energy needed to remove an electron

Question 40

When does ionization energy increase?

Answer 40

as you move from left to right and up periods

Question 41

successive ionization energies

Answer 41

energy needed to remove a second, third, fourth, etc electron

Question 42

Why does successive ionization energy increase?

Answer 42

removing electrons makes a positive ion which makes it harder to remove electrons

Question 43

When does a jump in ionization energy occur?

Answer 43

when an electron is pulled from the noble gas core

Question 44

electronegativity

Answer 44

atom’s ability to attract electrons in chemical bond

Question 45

When does electronegativity increase?

Answer 45

as you move left to right and up a period

Question 46

electron affinity

Answer 46

energy change that occurs when an atom gains an extra electron

Question 47

electron affinity

Answer 47

energy change that occurs when an atom gains an extra electron

Question 48

When does electron affinity increase?

Answer 48

as you move left to right across period and up a period