Chapter 5

Question 1

In 1860 who presented a method for accurately measuring the relative atomic masses of the elements?

Answer 1

Stanislao Cannizzaro

Question 2

Who published their first period table in 1869? How did they organize it?

Answer 2

Dimitri Mendeleev
- placed known elements in order using their atomic masses
- recognized that certain properties repeated themselves “peridoically”
- rearranged the elements so that elements with similar properties appeared together in his table
- his procedure left empty spaces from elements that had not been discovered

Question 3

In 1911 Henry Mosley discovered what?

Answer 3

That the periodic table fit better when the elements were placed in order according to their increasing positive charge

Question 4

What did Moseley’s work lead to?

Answer 4

The modern definition of atomic number and that atomic number is the basis for organization of the periodic table not atomic mass

Question 5

What is the periodic law?

Answer 5

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

Question 6

How is the periodic table arranged?

Answer 6

Arranged in order of their atomic numbers so that elements with similar properties fall in the same column or group

Question 7

A group/family

Answer 7

The vertical columns of the periodic table

Question 8

Period

Answer 8

The horizontal rows of the periodic table

Question 9

What are the noble gases?

Answer 9

The group 18 elements which are not reactive (inert)

Question 10

What are lanthanides

Answer 10

Elements 58-71 at the bottom of the periodic table that are very similar in properties; represent the 4th energy level “f” orbital block elements from period 6

Question 11

What are actinides?

Answer 11

Elements 90-103 are all radioactive and represent the 5th energy level “f’” orbital block elements from period 7

Question 12

In each of groups 1-18, the differences between the atomic numbers of successive elements are 8.8.18.18.32

Question 13

The electron configuration of an atom’s highest occupied energy level governs…

Answer 13

the atom’s atomic properties

Question 14

How is the length of each period determined?

Answer 14

By the number of electrons that can occupy the sublevels being filled in that period

Question 15

S-Block Elements

Answer 15

Groups 1 and 2; the s orbital is being filled in the energy level equal to the period number

Question 16

Alkali metals

Answer 16

Group 1 metals; so reactive that do not exist as pure elements in nature

Question 17

Alkaline-earth metals

Answer 17

Group 2 metals that also are very reactive and do not exist alone in nature

Question 18

P-block elements

Answer 18

13-18; the 3 “p” orbitals are being filled in the energy level equal to the period number

Question 19

Halogens

Answer 19

Group 17 elements

Question 20

D-Block elements (transition metals)

Answer 20

3-12, in which 5 “d” orbitals are being filled in the energy level equal to the period # minus 1

Question 21

F block elements

Answer 21

two rows at the bottom of the periodic table that represent 7b “f” orbitals being filled in the energy level that is equal to the period number minus 2

Question 22

What is atomic radius

Answer 22

One-half the distance between the nuclei of identical atoms that are bonded together

Question 23

As you go across a period the positive charge of the nucleus _______, the pull exerted on the electron cloud _______ and the atomic radius of the elements decreases across the period.

Answer 23

increases; increases

Question 24

As you move down a group, each successive element adds an energy level so the atomic radii _________ down a group

Answer 24

increase

Question 25

What is an ion?

Answer 25

An atoms or group of atoms that has a positive or negative charge

Question 26

What is ionization?

Answer 26

Any process that results in the formation of an ion

Question 27

What is ionization energy?

Answer 27

The amount of energy required to remove one electron from a neutral atom of an elements

Question 28

Ionization energies of the main group elements ________ across a period

Answer 28

increase

Question 29

Ionization energies of the main group elements usually _________ down a group

Answer 29

decrease

Question 30

Group 1 metals have the __________ ionization energies. Why?

Answer 30

lowest; they love electrons easily

Question 31

Group 18 have ___________ ionization energies. Why?

Answer 31

high; don’t lose electrons easily

Question 32

What is electron affinity?

Answer 32

the energy change that occurs when an electron is acquired by a neutral atom

Question 33

What is a cation?

Answer 33

An ion with a positive charge due to the loss of electrons

Question 34

Anion

Answer 34

An ion with negative charge due to the gain of electrons

Question 35

Halogens ______electrons most readily. What dies this cause?

Answer 35

gain; high reactivity

Question 36

When atoms become ions their radius…

Answer 36

changes

Question 37

Formation of a cation leads to a ______ in atomic radius

Answer 37

decrease

Question 38

Formation of an anion leads to a ________ in atomic radius.

Answer 38

increase

Question 39

What are valence electrons?

Answer 39

Electrons available to be gained, lost, or shared by atoms in the formation of chemical bonds to make compounds

Question 40

Where are valence electrons?

Answer 40

In the highest energy levels and often located in incompletely filled orbitals

Question 41

What is electronegativity

Answer 41

A measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound

Question 42

Electronegativity tends to ________ across a period and either _________ or remain ________ down a group.

Answer 42

increase; decrease; the same

Question 43

What is the most electronegative of the elements?

Answer 43

Fluorine (F)