Matter and Chemical Bonding

Question 1

Atomic Size (Periodic Trend)

Answer 1

(Measured in terms of radius) Top to bottom (groups): atomic size increases due to increasing electron shells

• Number of electron shells
• The shielding effect of the inner electrons
• Larger number of protons=more electron pull in smaller radius

Question 2

Ionization Energy

Answer 2

The minimum energy required to remove the most loosely held electron from an atom or an ion at its gaseous, ground state.

Question 3

IE down a group (Periodic trend)

Answer 3

Decrease in magnitude of IE due to decrease in effective nuclear charge.
(increasing shielding effect)

Question 4

IE across a period

Answer 4

Increase in magnitude from left to right due to number of protons (no added shielding)

Question 5

Electron Affinity

Answer 5

The energy change associated with the addition of an electron to an atom or an ion at its gaseous, ground state.

Question 6

EA down a group

Answer 6

Becomes more endothermic/ less exothermic from top to bottom

- less favourable to nucleus to attract incoming electrons (shielding increase)

Question 7

EA across a period

Answer 7

Becomes more favourable (exothermic) from left to right.

-Increase of protons=the added attraction

Question 8

Electronegativity

Answer 8

A measure of the ability of an atom to attract electrons in a bond.

• increase from left to right
• reactive metals have less electronegativity values then reactive non-metals
• electronegativity difference between reactive metal and reactive non-metal leads to a formation of an ionic bond.

Question 9

John Dalton Experiment (1809)

Answer 9

• All matter is made up of small particles called atoms (cannot be divided)
• atoms reorganized in chemical reactions, not changed
• Law of conservation of mass
• Law of definite proportion

Question 10

Isotope

Answer 10

Atoms that have a same number of protons but different number of neutrons.

Question 11

Homogeneous

Answer 11

The mixture of 2 or more substances has a uniform composition throughout.

Question 12

Heterogeneous

Answer 12

The substances can be determined from each other in a mixture of 2 or more substances.

Question 13

Aqueous Solution

Answer 13

a solution that contains water

Question 14

Isotopic Abundance

Answer 14

The amount of a given isotope of an element that exists in nature, expressed as a percentage of the total amount of this element.

Question 15

Atomic Radius

Answer 15

Measured from the centre nucleus to the outer-most valence electron.

Question 16

Effective Nuclear Charge

Answer 16

The apparent nuclear charge, as experienced by the outermost electrons of an atom, as a result of the shielding by the inner-shell electrons.

Question 17

VSEPR

Answer 17

Valence Shell Electron Pair Repulsion

Question 18

Bond Polarity

Answer 18

The sharing of electrons between atoms.
Non-polar: Electrons shared evenly between 2 atoms
Polar: One atom has greater attraction with the electrons than the other.

Question 19

Ionic Bond

Answer 19

The attractive electrostatic force between a negative ion and a positive ion

Question 20

Ionic Compound

Answer 20

A chemical compound composed of ions that are held together by ionic bonds.

Question 21

Covalent Bond

Answer 21

The attraction between atoms that results from the sharing of electrons

Question 22

Polyatomic Ion

Answer 22

a molecular compound that has an excess or a deficit of electrons and thus has a charge.

Question 23

Molecular Polarity

Answer 23

Polar molecules interact through dipole-dipole intermolecular forces and hydrogen bonds.

Question 24

Intermolecular Bonds

Answer 24

Electrical forces of attraction between neighbouring molecules (different molecules)

Question 25

Intramolecular Bonds

Answer 25

Forces of attraction which hold an individual molecule together (same molecule)

Question 26

London Dispersion Forces

Answer 26

Induced/ temporary dipole interactions