Year 10 Chemistry

Reaction Types and the Periodic Table

Endothermic reactions

Absorb energy from surroundings in the form of heat

Examples of endothermic reactions

Evaporation, photosynthesis, melting ice, cooking

Exothermic reactions

Release energy into surroundings in the form of light, electricity or heat.

Examples of exothermic reactions

Explosions, ice forming, burning substances, respiration

Factors impacting reaction rate

Temperature, concentration, particle size/surface area, use of catalyst

Effect of temperature on reaction rate

Warmer temperature causes particles to have more energy, move faster, and result in more successful collisions

Effect of concentration on reaction rate

Increased concentration of particles causes more collisions to occur and therefore a faster reaction

Effect of particle size/surface area on reaction rate

Decreased particle size/increased surface area results in more exposed particles, causing more collisions

Effect of catalyst on reaction rate

Speeds up rate of reaction by lowering activation energy, making it easier to overcome activation energy barrier

Chemical reaction type 1

Composition, TWO or more reactants join to form a SINGLE product, A+B→AB

Chemical reaction type 2

Decomposition, a SINGLE reactant breaks down into TWO or more products, AB→A+B

Chemical reaction type 3

Single displacement, one element is substituted for another in a compound, A+BC→B+AC

Chemical reaction type 4

Double displacement, exchange of ions between TWO reactions to form TWO NEW compounds, AB+CD→AD+BC

Gas test for oxygen

Relights glowing splint

Gas test for carbon dioxide

Extinguishes a flame

Gas test for hydrogen

Pop test

Indicators of a chemical reaction having taken place

Temperature change, colour change, fizzing/gas produced, precipitate formed

Collision theory

For a collision to be successful and create a new product, particles must collide with enough energy to overcome the activation energy barrier, and with correct orientation.

Activation energy

The amount of energy required for a chemical reaction to occur

What is the atomic number equal to?

Number of protons

Mass number

Number of protons + number of neutrons

Similarities of a group on periodic table

Same chemical properties and number of valence electrons

Similarities of a period on periodic table

Same number of occupied electron shells

Subshell notation order

s, p, d, f

How many electrons does ‘s’ subshell hold?

2

How many electrons does ‘p’ subshell hold?

6

How many electrons does ‘d’ subshell hold?

10

How many electrons does ‘f’ subshell hold?

14

Isotope definition

Different forms of the same element, same number of protons but different number of NEUTRONS. Atoms react by gaining or losing electrons.

Electronegativity

How strongly an atom attracts electrons towards itself. Greater electronegativity = greater ability to attract. Metals low, non-metals high.

Ionisation energy

The energy required to remove a valence electron from an atom.

Families on the periodic table

Alkali metals (group 1), Alkali earth metals (group 2), Halogens (group 17), Noble gases (group 18), Transition metals (group 3-12)

Features of alkali metals (group 1)

Highly reactive with non-metals, only one valence electron

Features of alkali earth metals (group 2)

Reactive with non-metals, 2 valence electrons

Features of Halogens (group 17)

Highly reactive with both metals/non-metals, only one valence electron missing from a full valence shell.

Features of Noble gases (group 18)

Non-reactive, stable due to full valence shell

Features of Transition metals (group 3-12)

Shiny, malleable, solid at room temp, good conductors of heat and electricity.

Metallic bonding

Between metal atoms, which have low ionisation energy and delocalised electrons.

Covalent bonding

Between non-metal atoms, which have high electronegativity and hold strongly to valence electrons. Two atoms bond to share electrons and obtain a full valence shell.

Ionic bonding

Between a metal and non-metal atom, metal atoms, which have low ionisation energy, give electrons to the non-metal atom to have a full valence shell. This makes the metal atom positive, and the non-metal atom negative, pulling them together.

Organic chemistry

Study of the chemistry of carbon compounds

Hydrocarbon

Any chemical compound composed exclusively of the elements carbon and hydrogen. Any compound that contains carbon-hydrogen bonds is called an organic compound.

Inorganic compound

Any compound that does not contain C-H bonds

Alkane

Hydrocarbons in which all the carbon-carbon bonds are single covalent bonds

Where are metals and non-metals located on the periodic table?

Metals on left and middle, non-metals on right

Alkanes up to 8C in order

Methane, ethane, propane, butane, pentane, hexane, heptane, octane

Molecular formula for methane

CH₄