Chapter 2

Question 1

Define Atomic mass

Answer 1

the average mass of the naturally occurring isotopes of an element

Question 2

Define atomic radius

Answer 2

the distance from the nucleus to the outermost occupied electron orbital in an atom

Question 3

State Aufbau principle

Answer 3

the procedure for assigning electrons to shells, subshells, and orbitals in the order of increasing energy.

Question 4

What is Azimuthal quantum number ?

Answer 4

the number designation (l) of an electron subshell.

Question 5

What is a closed shell?

Answer 5

a valence shell in an atom that has the maximum number of electrons allowed by the Pauli Exclusion Principle.

Question 6

What is electron affinity?

Answer 6

the amount of energy released when an electron is added to a neutral atom in the gas phase

Question 7

What is electronegativity ?

Answer 7

a measure of the tendency of an atom to attract electrons from another atom in a chemical bond

Question 8

What is electron configuration?

Question 9

What is an excited state?

Answer 9

higher energy state of an atom arising from the absorption of energy and the transition of electrons to higher orbitals.

Question 10

Define : Principal quantum number

Answer 10

the number designation (n) of an electron shell. Proton a positively charged particle present in all atomic nuclei.

Question 11

What is meant by : quantized ?

Answer 11

a quantity that is restricted to certain allowed values

Question 12

How many naturally occurring elements are there?

Answer 12

98

Question 13

What three particles make up an atom and what are their charges?

Answer 13

1. Proton > positively charged
2. Neutron > unchanged
3. Electron > negatively charged

Question 14

Where is the majority of the mass of an atom located?

Answer 14

Nucleus

Question 15

Where is the majority of the volume of an atom located?

Answer 15

Electrons in their orbitals

Question 16

What is the atomic number of an atom equal to?

Answer 16

Number of protons in the nucleus

Question 17

What is the mass number of an atom equal to?

Answer 17

Number of protons + number of neutrons

Question 18

What are the atomic symbols of the following elements: (a) boron, (b) antimony, (c) silver, (d) tungsten, (e) astatine, (f) iron?

Answer 18

a. B
b. Sb
c. Ag
d. W
e. At
f. Fe

Question 19

What are the names of the following elements:(a) Cl , (b) Cu , (c) Au , (d) Tl , (e) Na , (f) Rn?

Answer 19

a. Chlorine
b. Copper
c. Gold
d. Thallium
e. Sodium
f. Radon

Question 20

What are isotopes?

Answer 20

Elements that have the same number of protons but different number of neutrons

Question 21

How atomic mass different from mass number?

Answer 21

Mass number is equal to the number of protons and neutrons in the nucleus of an atom
Atomic mass average mass of all naturally occurring isotopes

Question 22

What determines the chemistry of an atom?

Answer 22

It’s electrons

Question 23

What is meant by electrons being quantized?

Answer 23

The energy of electrons is being restricted to certain allowed values

Question 24

What is the quantum number that designates an electron shell? What is its letter designation?

Answer 24

Principle of quantum number (n)

Question 25

What is the quantum number that designates an electron subshell? What is its letter designation?

Answer 25

Azimuthal quantum number (l)

Question 26

What is the quantum number that designates the spatial orientation of an orbital? What is its letter designation?

Answer 26

Magnetic quantum number (m)

Question 27

What is the Pauli Exclusion Principle?

Answer 27

No two electrons can have the same four quantum numbers

Question 28

List the four quantum numbers, their letter designations, and their allowed values.

Answer 28

1. Principle of quantum number ....(n) .... 0,1,2,3.. 2. Azimuthal quantum number .... (l) .... -1,0,1.. 3. Magnetic quantum number .... (m) .... +l , 0 ,-l 4. Spin quantum number .... (s) .... -½ , + ½

Question 29

What is the ground state of an atom?

Answer 29

Electronic configuration with the lowest possible energy

Question 30

What creates an atomic excited state?

Answer 30

Absorption of energy causing an electron to move to a higher energy orbital

Question 31

What is released when an electron falls from a higher orbital to a lower one?

Answer 31

Energy inform of light

Question 32

What is the Aufbau principle?

Answer 32

Procedure of assigning electrons into shells , sub shells and orbitals in oder of increasing energy

Question 33

What is Hund’s Rule?

Answer 33

Electrons will occupy orbitals individually before occupying them in pairs

Question 34

List the electron subshells in the order of increasing energy.

Answer 34

s