Chemistry Yr 10

alkali metal

element found in group 1 of the periodic table

alkaline earth metal

element found in group 2 of the periodic table

halogen

element found in group 17 of the periodic table

noble gas

gaseous element found in group 18 of the periodic table

metal

elements found on the left hand side of the periodic table that are shiny, malleable, ductile and good conductors of heat and electricity

non-metal

elements that are found on the right hand side of the periodic table

anion

a negatively charged ion

cation

a positively charged ion

electron configuration

the arrangement of electrons in each electron shell surrounding an atom

valence electron

an electron located in the outermost electron shell

ion

an atom that has gained or lost electrons, resulting in a positive or negative charge

compound

a pure substance made contains particles made up of 2 or more different atoms bonded together

covalent compound

different non-metal atoms chemically bonded together

covalent molecular compound

covalent compound that forms molecules CO2, H2O

covalent network compound

covalent compound in network (3D grid) form. Diamond, graphite

chemical reaction

a change in which a new substance is formed (original reactant particles have been rearranged to form new product particles)

chemical equation

a shorthand way of describing what happens in a chemical reaction (products and reactants)

product

a substance formed as a result of a chemical equation

reactant

a substance present at the start of a reaction

acid

a substance that produces H+ ions in solution

Base

a substance that produces OH- ions in solution

neutralisation

the reaction between an acid and base

strong (acid)

a high proportion of molecules produce ions in solution; said to ‘completely ionise

weak (acid)

a low proprtion of molecules produce ions in solution; said to ‘partially’ ionise

solute

the dissolved substance in a solution

solvent

the substance that dissolves other substances (usually present in a greater quantity)

solubility

a measure of how easily a substance dissolves in a solvent

soluble

is able to be dissolved in a solvent

insoluble

doesn’t dissolve

precipitate

insoluble solid produced in a chemical reaction

concentration

a measure of how much solute is dissolved is a given volume of solution can be described qualitatively and quantitatively

dilute

a small amount of solute dissolved in a given volume of solution

concentrated

a large amount of solute dissolved in a given volume of solution

how are electrons arranged?

They are arranged in energy levels (shells) around the nucleus

How many electrons can fit in each shell?

1: 2
2: 8
3: 8
4: 2

valence electrons

electrons located on the outer electron shell

groups

determine how many electrons are in the valence shell (columns)

periods

the number of electron shells (rows)

what shell do electron dot diagrams show?

valence shell/electrons

What are the characteristics of alkali metals? (group 1)

• 1 valence electron

• loses one electron to become stable

• forms ion with +1 charge

what are the physical qualities of alkali metals (group 1)

• soft

• shiny when cut

• low melting point

• highly reactive

• react with water

what are the characteristics of alkaline earth metals? (group 2)

• 2 valence electrons

• loses 2 electrons to become stable

• forms ion with +2 charge

what are the physical qualities of alkaline earth metals? (group 2)

• relatively soft metal

• still quite low melting point

• very reactive (not as much as group 1)

• react with water

what are the characteristics of halogens? (group 17)

• 7 valence electrons

• gain 1 electron to become stable

• forms ion with -1 charge

what are the physical qualities of halogens (group 17)

• F and Cl are gases

• Br is a liquid

• I and At are solids

what are the characteristics of noble gases? (group 18)

• full outer electron shell

• very unreactive

• gas at room temperature

why are noble gases generally un-reactive?

• full valence shell

• means they are already stable and don’t need to bond (ionic or covalent) to become stable

ionic bond

• electrostatic attraction between oppositely charged ions

• makes a lattice structure

• between a metal and non-metal element

• when atoms transfer electrons to become stable

covalent bond

• chemical bond that is formed when two non-metal atoms share electrons to achieve a full outer shell

• neutral particles with no overall charge

• between 2 non-metals

• when 2 atoms share valence electrons to become stable

what are the properties of ionic solids?

• hard

• brittle

• high melting point

• non-conductors of electricity

• will conduct in liquid state

what are the properties of covalent molecular substances?

• soft solids

• low melting point

• non-conductor of electricity

iodine

I^(-)

hydroxide

OH^(-)

Nitrate

NO3^(-)

oxide

O^(2-)

sulfide

S^(2-)

carbonate

CO3^(2-)

Sulfate

SO4^(2-)

nitride

N^(3-)

phosphide

p^(3-)

phosphate

PO4^(3-)

ammonium

NH4^(+)

covalent bonding

• between 2 non-metal atoms, no electrons are transferred - they are shared

• can achieve stability without gaining/losing electrons

• creates a ne=utral particle with no overall charge

diatomic molecules

• 2 identical atoms sharing electrons

• H2, N2, F2

covalent compounds

• 2 different non-metal atoms share electrons

• H20

• electrically neutral - carry no charge since protons = electrons

properties of covalent molecules

• soft

• low melting/boiling point

• non-conductors

1

mono

2

di

3

tri

4

tetra

5

penta

6

hexa

7

hepta

8

octa

9

nona

10

deca

rules for naming covalent compounds

• first element: use prefix only if more than 1 atom

• second element: always use prefix and change ending to ide

what are the changes when a chemical reaction opccurs

• colour change

• solid preciptate produced

• new substance formed

• gas produced

• heat and light produced

what happens to atoms during chemical reactions?

• reactant particles are rearranged to form product particles

• bonds are broken and new bonds are formed

• energy is released or absorbed (exothermic, release and endothermic, absorb)

how to represent chemical reactions

• using word and chemical equations

• the law of conservation of mass - balancing equations

why equations must balance

• matter is neither create or destroyed in a chemical reaction

• total mass of reactants must equal total mass of products

• reactant - starting materials

• products - resulting materials

how to balance

1. write equation

2. list elements

3. add coefficients

4. re-check counts

observing chemical reactions

• what do reactants look like?

• what happens during the reaction?

• what do the products look like?

acid

• substance that produces H^+ ions in a solution

• corrosive

• sour taste

• turn blue litmus paper red

• conducts electricity

• pH less than 7

common acids

• HCl hydrochloric acid

• HNO3 nitric acid

• H2SO4 sulfuric acid

• CH3COOH ethanoic acid

common acids - hydrochloric acid

HCl

common acids - nitric acid

HNO3

common acids - sulfuric acid

H2SO4

common acids - ethanoic acid

CH3COOH

base

• substance that produces OH^- ions in solutions

• caustic

• bitter taste

• soapy/slimy feel

• turn red litmus paper blue

• conducts electricity

• pH more than 7

common bases - sodium hydroxide

NaOH

common bases - potassium hydroxide

KOH

common bases - calcium hydroxide

Ca(OH)2

common bases - barium hydroxide

Ba(OH)2

indicators

• chemical that changes colour with pH and is used to determine whether a solution is an acid or base

• universal indicator and litmus paper

reactions od acids + bases

acid + base ——> H2O and salt

• neutralisation reaction

• H^+ from the acid and OH^- from the base combine to form water

• leftover parts of the acid and base combine to form a salt

hack for acid and base reactions

• the second part of the aid and the first part of what it reacts with makes the salt

• HCl + NaOH ——> H2O + NaCl

naming salts

• hydrochloric acid forms ‘chloride’ salts —— HCl (-1 charge)

• nitric acid forms ‘nitrate’ salts —— HNO3 (-1 charge)

• sulfuric acid forms ‘sulfate’ salts —— H2SO4 (-2 charge)

acid and base observations

• don’t write ‘no reaction’ as a reaction is happening and you can’t see it

• write; 2 colourless liquids are mixed, a colourless solution is formed

hydrochloric acid/chloride salt

HCl (-1 charge)