SNS - General Chemistry - The Periodic Table

Question 1

The Periodic Table

Groups

Answer 1

Atoms of the same group have the same number of valence electrons. They are more similar to each other than atoms of the same period

Question 2

The Periodic Table Periods

Answer 2

Atoms of the same period have the same principal quantum number - number of shells

Question 3

The Periodic Table Trends Atomic Radii

Answer 3

Increase as you move down and to the left. Within a group, the radius increases downwards as each period has an additional outer principal energy level of electrons (shell) Radius decreases as you move to the right as additional protons in the nucleus create a stronger positive charge that is able to draw electrons towards the nucleus Radii of cations are always smaller than neutral atoms of the same element due to lessene electron-electron repulsion. Anions are always larger

Question 4

The Periodic Table Trends Ionisation Energy

Answer 4

Energy needed to remove an electron from an atom Increases as you move up and to the right Helium has the highest ionisation energy

Question 5

The Periodic Table Trends Electronegativity

Answer 5

Measure of the ability of an atom to acquire an additional electron. Increases as you move up and to the right Fluorine has the highest electronegativity

Question 6

The Periodic Table Trends Electron Affinity

Answer 6

Energy required to add an electron to an atom Increases as you move up and to the right. Closely related concept to electronegativity Fluorine has the highest electron affinity

Question 7

The Periodic Table Trends Melting and Boiling Points

Answer 7

Tend to decrease from top to bottom of a group for metals. Non-metals show an increase from top to bottom

Question 8

The Periodic Table Group Characteristics Group IA

Answer 8

Alkali metals Metallic character increases as you move down the group React easily with non-metals (one electron in outer principal energy level)

Question 9

The Periodic Table Group Characteristics Group IIA

Answer 9

Alkaline Earth Metals Two electrons in outer principal energy level

Question 10

The Periodic Table

Group Characteristics

Group IIIB-VIIIB

Answer 10

Transition Elements

Have unusual characteristics

Most have metallic character

Good electrical conductors - d electrons are held only loosely by the nucleus and are relatively mobile contributing both to good conduction and malleability

Have various oxidation states - are capable of losing various electrons from s- and d-orbitals of their valence shells. Because of this, may form many different ionic and partiallt ionic compounds

Question 11

The Periodic Table Group Characteristics Group VIIA

Answer 11

Halogens Seven electrons in outer shell Fluorine has the higherst electronegativity

Question 12

The Periodic Table Group Characteristics

Group 0

Answer 12

Noble gases Non-reactive due to full outer shells No electronegativity

Question 13

Z_eff

Answer 13

Effective nuclear charge - the attractive pull of the nucleus for electrons

The greater this is, the greater the electron affinity will be

Question 14

Characteristics

Metals

1. States, 2. Melting points, 3. Densities, 4. Properties, 5. Atomic radii, 6. ionization energies, 7. Electronegativities, 8. Conduction of electricity and heat

Answer 14

1. Solid at room temp (except mercury)
2. High
3. High
4. Malleable, ductile
5. Large - few electrons in the valence shell of a metal atom can be easily removed
6. Low - as above
7. Low - as above
8. Good - as valence electrons can move freely

Question 15

Characteristics

Non-metals

1. Properties, 2. ionization energies, 3. Electronegativities, 4. Conduction of electricity and heat

Answer 15

1. Generally brittle in solid state. Most share the ability to gain and lose electrons easily but otherwise exhibit a range of different chemical behaviours and reactivities
2. High
3. High
4. Usually poor

Question 16

Characteristics

Metalloids

1. Melting points, 2. Densities, 3. Properties, 4. ionization energies, 5. Electronegativities, 6. Conduction of electricity and heat

Answer 16

1. Vary widely
2. Vary widely
3. Found along the line between metals and non-metals
4. Lie between those of metals and non-metals
5. As above
6. As above