Topic 1 - Definitions

Question 1

Atomic number

Answer 1

of protons

Question 2

Atomic mass

Answer 2

of protons + # of neutrons

Question 3

Periods

Answer 3

Horizontal rows on the periodic table, helps identify the amount of electrons in an atom’s valence shell.

Question 4

Groups

Answer 4

Vertical columns on the periodic table

Question 5

Ionic bonding

Answer 5

bond between a M+NM; donates electrons to the other atom in the bond

Question 6

Covalent Bonding

Answer 6

Co - to share electrons (NM + NM) –> polar covalent + non-polar covalent
Bond where valence electrons are shared equally between atoms usually occurring between non-metals

Question 7

Metallic bonding

Answer 7

Bond between 2 metals; governed by the metal activity series

Question 8

Valency

Answer 8

Combining power of an element which is equal to the number of electrons added, removed or shared when it is bonded with other atoms

Question 9

Atomic radius

Answer 9

Measures the size of an atom and is defined as the average distance from the centre of the nucleus to the boundary of the valence shell

Question 10

Force of attraction

Answer 10

How much the outer electrons (-) are attracted to the nucleus –> easily lost

Question 11

Electronegativity

Answer 11

The tendency of an atom to attract electrons during a chemical bond

Question 12

Chemical property

Answer 12

characteristics or behaviour of a substance that may be observed when it undergoes a chemical reaction

Question 13

Electron Configuration - Subshell notation

Answer 13

S shell - holds max of 2 electrons (left side of the periodic table: metals, including helium)
P shell - holds max of 6 electrons (right side of the periodic table: non-metals)
D shell - holds max of 10 electrons (centre of the periodic table: transition metals)

Question 14

Polyatomic ions

Answer 14

Two or more atoms in a bond giving the compound an overall charge

Question 15

Electron affinity

Answer 15

The change in energy (kJ/mole) of a neutral atom when an electron is added to the atom, forming an anion

Question 16

VSEPR Theory

Answer 16

Valence Shell Electron Pair Repulsion Theory

• the role of electron pairs in shaping the arrangement of atoms in molecules
• the theory proposes that all electron pairs in atoms repel each other mutually

Question 17

Predicting shapes of simple molecule:

Answer 17

1. Identify the atom of highest covalence and have it in the centre
2. Draw an electron-dot diagram
3. Count the number of bonding + non-bonding pairs
4. Identify arrangement of electron pairs
5. Identify electron shape and draw

Question 18

Polarity

Answer 18

The distribution of electrical charge over the atoms joined by the bond

Question 19

Polar Covalent

Answer 19

• Have a negative and positive pole
• Happens when 2 non-metals are in a bond
• One has a higher electronegativity than the other
• This causes one atom to be slightly positive and the other slightly negative
• All halogens are polar covalent (H2, F2, BR, Cl2, O2, I2, N2)
• Polar covalent substances dissolve easier than non-polar covalent

Question 20

Non-Polar covalent

Answer 20

• Between the same element
• Happens when atoms are of equal electronegativity or due to the molecular shape
• Both poles are the same charges (+ , +) or (- , -)

Question 21

Predicting if the covalent bond is Polar or Non-Polar

Answer 21

1. Assign partial charges (S-, S+)
   
   • due to electronegativity
   • anything with a low electronegativity will usually be S+
2. Assign an arrow to indicate area of low E.N and area of high E.N (low EN = + high EN = - )

Question 22

Solution

Answer 22

A homogenous mixture consisting of a solute dissolved into a solvent
- solute: substance that is being dissolved
- solvent: dissolving medium
When one substance dissolves into another, a solution is formed

Question 23

Water (H2O)

Answer 23

Known as the universal solvent as it can dissolve the most substances

Question 24

Ionic Compounds

Answer 24

Can conduct electricity when molten (liquid) or in aqueous solution (dissolved in water) because their ions are free to move from place to place

Question 25

Dissociation

Answer 25

A process where ionic substances break apart when dissolved in water

Question 26

Linear

Answer 26

Any molecular with only two atoms. Also, if same atom, non-polar halogens (diatomic), N2, O2, H2. If 2 atoms are different, they are polar

Question 27

What is #protons equal to?

Answer 27

#Electrons

Question 28

Polyatomic Ions Tip: If it ends with 'ate' the polyatomic ion has...

Answer 28

More oxygen than 'ite'

Question 29

Polyatomic Ions Tip: If it ends with 'ide' it has...

Answer 29

No oxygen

Question 30

What is physical change?

Answer 30

A change observed that does not alter the chemical identity of the molecule but changes state of matter. Solid --> Liquid --> Gas

Question 31

What are the physical properties of materials? (elements, compounds, mixtures)

Answer 31

- Melting point - Boiling point - Electrical conductivity - Thermal conductivity - Mass

Question 32

What is melting point?

Answer 32

- The temperature range which causes the material to change from solid to liquid - Chemistry concept: Heat energy causes the atoms to vibrate and in turn faster (kinetic energy) - Atoms vibrate away from each other causing the bond between the molecules to be less tightly packed

Question 33

What is boiling point?

Answer 33

- The temperature range which causes the material to change from liquid to gas - Chemistry concept: Heat energy causes the atoms to vibrate and in turn faster (kinetic energy) - Atoms vibrate away from each other causing the bond between the molecules to be less tightly packed - It is the result of transferring higher heat energy compared to melting point

Question 34

What are the characteristics of metals?

Answer 34

- Shiny - Mostly solid at room temperature, some exceptions are liquids - conducts electricity - Conducts heat - Ductile - Malleable - Not all metals react the same though

Question 35

What are some common reactions with metals?

Answer 35

1. When metals react with oxygen, they produce a metal oxide. E.g. calcium + oxygen --> calcium oxide 2. When metals react with water, they produce a metal hydroxide E.g. sodium + water --> sodium hydroxide 3. When metals react with acids, they produce metal salt and hydrogen gas E.g. magnesium + hydrochloric acid --> magnesium chloride + hydrogen (THESE REACTIONS DO NOT OCCUR FOR EVERY METAL, IT DEPENDS ON THEIR REACTIVITY)

Question 36

Trigonal Planar

Answer 36

- A molecular with three electron groups orients the three groups as far apart as possible. - They adopt the positions of an equilateral triangle - 120° apart and in a plane shape.

Question 37

Inter and Intra Molecular Bonds

Answer 37

Intermolecular bonds are the forces between the molecules | Intramolecular bonds are the forces within two atoms in a molecule

Question 38

Primary bonds or intramolecular forces

Answer 38

Strong attractive forces that joins atoms in a molecule

Question 39

Secondary interactions or intermolecular forces

Answer 39

Weak attraction forces that joins 2 elements, which includes London dispersion-forces, dipole-dipole interactions and hydrogen bonding

Question 40

London dispersion forces

Answer 40

Exists between all molecules. Their strength depends on the size and shape of the molecules. - weakest intermolecular force - temporary attractive force that occurs when the electrons in 2 adjacent atoms occupy positions that make the atoms form temporary dipoles

Question 41

Ionization energy

Answer 41

The amount of energy needed to remove an outer electron from an atom and make it into an ion