Unit 1 The periodic table

Question 1

Define relative/natural abundance

Answer 1

Is a consistent ratio found in nature for given elements.

Question 2

What is atomic mass of an element?

Answer 2

Is the weighted average of the mass of its isotopes.

Question 3

Define weighted average

Answer 3

means some values have greater impact of the average than others.

Question 4

What are some important points when calculating relative abundance?

Answer 4

• the larger isotope number is “x”

- the first step to isolating “x” is to multiply both sides by 100

Question 5

What are the two rules that need to be followed for adding electrons to the orbital box diagrams?

Answer 5

1) Pauli Exlusion Principle

2) Hund’s Rule

Question 6

Describe the two rules for the orbital box diagram

Answer 6

Pauli Exclusion Principle:
- The maximum number of electrons in each orbital is two. If two electrons are in one orbital, they must have opposite spins.
Hund’s rule:
- When adding electrons to a sublevel with more than one orbital, the electron spins must be all the same until each orbital has one electron.

Question 7

What is the Aufbau principle?

Answer 7

Electrons fill sublevels starting with the lowest energy level up to highest energy.

Question 8

State the limitations of the Bohr Model

Answer 8

Assumes or suggests:

• electrons orbit the nucleus/is predictable
• shape of orbits/shells are all spherical
• an incorrect scale of an atom
• energy of electrons in a level are all the same

Question 9

What are the exceptions to the full electron configuration?

Answer 9

• Nearly full “d” sublevels will take an electron from the closest “s” sublevel to be full
• Nearly half full “d” sublevels will take an electron from the closest “s” sublevel to be half full

Question 10

What is the electromagnetic spectrum order in increasing energy?

Answer 10

Radiowaves, Microwaves, infrared, visible, untraviolet, x-rays, gamma rays

Question 11

How are the elements of the periodic table arranged?

Answer 11

By increasing atomic number

Question 12

What is the significance of the periodic groups?

Answer 12

The elements in the groups have similar chemical properties.

- same number of valence electrons

Question 13

What is the name of group 1?

Answer 13

Alkali metals

Question 14

What is the name of group 2?

Answer 14

Alkaline earth metals

Question 15

What is the name of groups between group 2 and 3?

Answer 15

Transition metals

Question 16

What is the name of group 6?

Answer 16

Chalcogens

Question 17

What is the name of group 7?

Answer 17

Halogens

Question 18

What is the name of group 0 (or 8)?

Answer 18

Nobel gasses or inert gasses

Question 19

What is the name of the two lower rows?

Answer 19

Rare earth elements

Question 20

What are the horizontal rows called and what is their significance?

Answer 20

Called periods

- the number of the period equals the number of energy levels in the ground state

Question 21

What is Atomic Radius?

Answer 21

The distance from the nucleus to the outermost electron.

Question 22

How do you find atomic radius?

Answer 22

Half the distance nuclei of two bonded atoms of the same element (ex. diatomic molecules)
- is estimated for non-identical atoms

Question 23

What is Ionic Radius?

Answer 23

Defined as the distance from the nucleus to the outermost electron of an ion

Question 24

Describe on general terms the ionic radius of the ions

Answer 24

• Cations loose electrons and are smaller than their respective atom, occurs for metals.
• Anions have gained electrons and are larger than their respective atom, occurs for non-metals.

Question 25

Define First Ionization Energy

Answer 25

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

Question 26

Define electronegativity

Answer 26

Is a relative measure (having no units) of the attraction an atom has for a pair of electrons that are shared with another atom.

Question 27

Define electron affinity

Answer 27

The energy released when one electron is added to an atom in its gaseous state. (only applies to non-metals)

Question 28

What is the periodic trend for atomic radius?

Answer 28

Atomic Radius: - increases down the group because an extra shell is added - decreases across the period because there are more protons

Question 29

What is the periodic trend for ionic radius?

Answer 29

Ionic Radius: - increases down the group because an extra shell is added - decreases across the period because there are more protons

Question 30

What is the period trend for ionization energy?

Answer 30

Ionization Energy: - decreases down the group because an extra shell is added - generally increases across the period because there are more protons

Question 31

What is the periodic trend for electronegativity?

Answer 31

Electronegativity: - decreases down the group because an extra shell is added - increases across the period because there are more protons

Question 32

What is the period trend for electron affinity?

Answer 32

Electron Affinity: - generally decreases down the group because an extra shell is added - generally increases across the period because there are more protons

Question 33

What is the general trend for melting point?

Answer 33

Melting Point: - For Alkali metals the melting point decreases down the group - For Halogens melting point increase down the group - Across periods 2 and 3 melting point increases from group 1 to 4 and generally decreases from group 4 to 0

Question 34

What is the first type of reaction?

Answer 34

2(Alkali metal) + 2H20 -> 2(Alkali metal ion) + 2OH^- + H2

Question 35

What is the second type of reaction?

Answer 35

2(Alkali metal) + Cl2 or Br2 -> 2(Alkali metal)Cl or Br

Question 36

What is the third type of reaction?

Answer 36

(greater electronegativity halogen)2 + 2(lower electronegativity halide ion) -> 2(greater electrnegativity halide ion) + (lower electronegativity halogen)2 2(greater electronegativity halide ion) + (lower electronegativity halogen)2 -> No reaction

Question 37

What is the fourth type of reaction?

Answer 37

Metal oxide + Water -> metal hydroxides

Question 38

What is the fifth type of reaction?

Answer 38

non-metal oxide + water -> acidic oxide