Periodic Table

Question 1

An atom contains which three particles?

Answer 1

1. neutrons
2. protons
3. electrons

Question 2

Where are electrons located and what is their charge? Protons? Neutrons?

Answer 2

• electrons: (-1) in electron orbitals surrounding the nucleus
• protons: (+1) in the nucleus
• neutrons: (0) in the nucles

Question 3

An atom is neutral when….?

Answer 3

The number of protons EQUALS the number of electrons.

Question 4

What is mass number?

Answer 4

Sum of the number of protons AND neutrons.

Question 5

What is atomic number?

Answer 5

Number of protons

(unique to each element)

Question 6

What are anions?

Answer 6

Negatively charged atoms that GAIN electrons.

Examples: OH^-, O₂^-

Question 7

What are cations?

Answer 7

Positively charged atoms that LOSE electrons.

Examples: Ag⁺, NH₄⁺

Question 8

What are isotopes?

Answer 8

Atoms with the same number of protons but DIFFERENT number of neutrons.

Question 9

Which ions do nonmetals form? Metals?

Answer 9

nonmetals: anions

metals: cations

Question 10

On a periodic table, what are groups (or families)?

Answer 10

Vertical columns

Question 11

On a periodic table, what are periods?

Answer 11

Horizontal rows

Question 12

What are the five characteristics of metals?

Answer 12

1. malleable
2. ductile
3. lustrous
4. good conductors of heat and electricity (valence electrons can move freely)
5. high melting points and densities

Nonmetals are essentially the opposite!

Question 13

What is effective nuclear charge (Z_eff)?

Answer 13

The electrostatic attraction between the nucleus and valence electrons.

This attraction decreases going down and left the periodic table because there are more electron shells which further separates the nucleus from the valence electrons.

Question 14

What are the four periodic trends?

Answer 14

1. atomic radius
2. ionization energy
3. electron affinity
4. electronegativity

Question 15

On a periodic table, how does atomic radius increase?

Answer 15

Atomic radius increases down and left.

Question 16

[Mnemonic]

ARDELL Lashes ⇒ ARIDAL

(how to remember how atomic radius increases)

Answer 16

ARDELL Lashes ⇒ ARIDAL

Atomic radius increases down and left.

Question 17

All periodic trends increase going up and right, with the exception of?

Answer 17

Atomic radius

Question 18

What is atomic radius?

Answer 18

The distance from the center of the nucleus to the outermost electron.

Cs has the biggest AR and He has the smallest AR.

Question 19

What is ionization energy?

Answer 19

The energy required to remove an electron from a gaseous atom (endothermic process).

He has the highest IE.

Question 20

What is first ionization energy? Second ionization energy?

Answer 20

1st ionization energy: energy required to remove the 1st electron to form a +1 cation

2nd ionization energy: energy required to remove the 2nd electron to form a +2 cation

1st IE < 2nd IE < 3rd IE etc.

Question 21

What is electron affinity?

Answer 21

The willingness of an atom to accept an additional electron (exothermic process).

Halogens are “greedy”. F has the highest EA and Fr has the lowest EA.

Question 22

What is electronegativity?

Answer 22

The pulling of electrons towards itself.

F has the highest EN and Fr has the lowest EN.

Question 23

What are the oxygen group (or Chalcogens)?

Answer 23

Elements in group 16.

Oxygen and Sulfur are the most important!

Question 24

Why are the transition elements so unique?

Answer 24

Multiple oxidation states

Example: Iron (Fe) can appear as Fe²⁺ or Fe³⁺

Question 25

What is coordination number?

Answer 25

The number of nearest neighbors a central atom has.

Example: The coordination number of carbon in methane (CH₄) is 4, because the central carbon has four neighbors.