C1&2 Keywords & atomic structure

Atom

Smallest unit of matter that still maintains the properties of the substance

Molecule

Two or more atoms, chemically combined and colvalently bonded

Element

same type of atom and cannot be broken down into simpler substances by chemical means

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds.

Chromatography

A technique that is used to separate the components of a mixture of soluble coloured substance, using a suitable solvent which is often water.

how it works

1. strip of chromatography paper

2. fold end around splint make sure it’s not touching bottom

3. draw pencil line

4. spot of each ink

5. put water but it does not go to the pencil line

6. draw solvent font after the solvent as almost reached the top

Rf value

In chromatography, the distance travelled by substance / distance travelled by solvent

Distillation

A process that separates the substances (often solute and solvent) in a solution based on their boiling points

Ion

An atom or group of atoms that has a positive or negative charge.

Isotope

Atoms of the same element that have different numbers of neutrons (proton no. smaller no.)

They have the same chemical properties because they have the same no. of electrons and therefore the same electron configuration)

mass number

the sum of the number of neutrons and protons in an atomic nucleus

proton number

the number of protons in the nucleus of an atom

Mixture

A combination of two or more substances that are not chemically combined

physical change

no new substances are formed, substances are physically combined, easily seperated

chemical change

A change in matter that produces one or more new substances and is not easily reversible

chemical change indicators

odor production, temperature change, gas production, precipitation, and color change

Electron

A subatomic particle that has a negative charge

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Solvent

A liquid substance capable of dissolving other substances

Solute

A substance that is dissolved in a solution.

when to purify and seperate using a suitable solvent

when one in the mixture is insoluble and the other is soluble, then able to filter out such as salt and sand

Chromatogram

A visible record showing the result of separation of the components of a mixture by chromatography.

Number of neutrons in Sodium-23

12

Nucleon Number (Mass Number) (A)

number of protons and neutrons in the nucleus

proton number (atomic number) (Z)

number of protons in the nucleus = number of electrons

Electronic configuration

is the same for ions too o2- 2, 8

Relative atomic mass

The weighted mean mass of an atom of an element taking % abundance into account

relative atomic mass formula

(average mass of each isostope type * abundance %)/100 + (and so on/100)

The relative atomic mass of an element given the following data:
Isotope 1 - mass number 63 and abundance 75%
Isotope 2 - mass number 65 and abundance 25%

63.5

The relative atomic mass of an element given the following data:
Isotope 1 - mass number 66 and abundance 50%
Isotope 2 - mass number 67 and abundance 50%

66.5

filtration

the process in which solid particles in a fluid is removed by the use of a filter that allows the fluid to pass through but retains the solid particles.

crystillisation

allows the liquid to evaporate slowly to form solids for a solid that may decompose at a very hot temperature. used mainly to obtain solid. as the solution cools (solubility decreases) and becomes more saturated, the solute forms pure crystals.

fractional distillation

seperating mixture of two or more liquids that have a boiling point closer than 25 degrees apart

no. vs electrons

noble gasses full outer shell

outer shell electron = group no.

occupied electron shells = period no.

amphoteric oxides

oxides that can react with acids and bases to produce salt and water because they can act as both acid and base thus show both their properties

answer should at least include:

Have acidic and basic properties

Will form salts when reacted with acids and alkalis

Will neutralise acids and alkalis

what are som amphoteric oxides

Al2O3 and ZnO

basic oxides

metal + oxygen (ionic compound) and they react with acids to produce salt and water forms alkaline solutions (purple colour)

what are some basic oxides

CuO and CaO

acidic oxides

nonmetal+oxygen colvalently bonded and react with water to produce an acidic solution (red)

examples of acidic oxides

SO2 and CO2

neutral oxides

• They are usually formed by non-metals.

• They do not dissolve easily in water.

• They do not form acidic or alkaline solutions.

• They do not react with acids or alkalis.

examples of neutral oxides

1. NO

2. carbon monoxide (CO)

what is the periodic table

an arrangement of elements in period and groups and in order of increaseing atomic number.

metallic and non-metallic characteristics

metals: larger atomic radius, conduct heat and electricity, usually high melting and boiling point, malleable, shiny

non-metals: smaller atomic radius, do not conduct h&t, usually low melting point, brittle, dull

alkali metals

relatively soft reactive metal with a low melting point (lithium sodium potassium)

react vigorously with water = metal hydroxide and hydrogen gas

balanced symbol equation (m = element)
2M(s) + 2H₂O(l) → 2MOH(aq) + H₂(g)

as you go down the group: increasingly soft

density increases

boiling point and melting point decreases (due to shielding where inner electrons block the attraction between outer electrons - less energy needed break the bonds)

group 7 halogens

diatomic non-metals

as you go down the group: increases density

decreasing reactivity

(room temp:)

chlorine: pale yellow-green gas

bromine: red-brown liquid

iodine: grey black solid

the diatomic family

oxygen, hydrogen, nitrogen + first 4 of halogens

displacement reactions

more reactive halogen replaces less reactive halogen in an ionic bond

net ionic equations

without the spectator ion (that don’t change in the reaction)

add charge to the seperated ionic compounds

transition metals

1. high density

2. high melting points

3. form coloured compounds

4. often act as catalysts as elements & in compounds

noble gases

unreactive monoatomic gas (inert)

specifically mention they do not need to loose/gain electrons to be stable

whats the ion that makes the solution alkaline in the case of alkaline metal + wa’er

hydroxide!!!!

CO₃

carbonate (valency 2-)

OH

hydroxide (valency 1-)`

NO3

nitrate (valency 1-)

SO4

sulfate (valency 2-)

NH4

ammonium (valency 1+)

practical: alkaline babies with water

what ion makes the solution alkaline

ALL PURPLE COLOUR and THEY ARE ALL SILVER

1. lithium: fizzing, produces hydrogen gas, floats

2. sodium: +flames and pop towards the end

3. potassium: + pink flames + pop

hydroxide makes it alkaline

iodine powder+aluminium powder +few drops of water

aluminium is silver(s), iodine is black solid(s) (produces purple vapor + aluminium iodide(s)

balanced: 2Al(s)+ 3I2(s)=2AlI3(s)

Describe the nature of the chemical bond between questions

1. state the bond

2. state what the atoms are (non-metals or metals?)

3. explain the bond ( ionic: strong attractive forces and attraction between oppositely charged ions) (covalent: electron is shared bewteen 2 non-metals, not donated by metal to non-metal)

account for differences between boiling points between colvalent + ionic questions

strong forces of attraction between ions so ionic bonds are very strong and requirs large amount of energy to overcome it

attractive forces for covalent much weaker so less energy required

STATE BOTH

electron config + periods

say how many shells they have occupied