C1 Key Concepts

Dalton model pre subatomic particles

• Atoms = smallest

• No Isotopes

• Chemical reactions = atoms rearagne

Dalton model post subatomic particles

• Atoms ≠ smallest

• protons = electrons amount but different neutrons

• Atoms of different elements have different numbers of protons and electrons

Describe the structure of an atom

Protons and neutrons densely packed in the nucleus in the middle electrons

Relative charge and mass

proton = mass 1 charge +1

neutron = mass 1 charge 0

electron = 1/200 charge -1

whats is mass number

protons + neutrons

describe atoms of a given element

same number of protons in the nucleus

describe isotopes of a given element

isotopes = same number of protons but different number of neutrons

calculate number of protons neutrons and electrons in atoms given the atomic number and mass number

• protons = atomic number

• electrons = atomic number

• neutrons = mass number - atomic number

why do do some elements have a non integer relative atomic mass

Isotopes - different versions of an element same atomic number different mass number

The atomic mass is a weighted average of the masses of an elements isotopes.

calculate the relative atomic mass of an element from the relative masses and amount of isotopes

(mass1 x amount1) + (mass2 x amount2)

how did Mendeleev organise the periodic table

• increasing atomic mass

• similar properties

• missing elements

how did Mendeleev know about elements not yet found

observing patterns or trends and leaving gaps for what should fit the pattern

mendeleevs arrangement of elements

• thought he had done it by increasing atomic mass

• isotopes, which he didn’t know existed yet, messed it up

meaning of atomic number

atomic number = protons

atomic number = where it is on the periodic table

electronic configuration

chlorine atomic number = 17

electronic configuration = 2.8.7

number of electrons in outermost shell =

what group the elements in

number of circles in electrons configuration

what period the elements in

ion

an atom with a positive or negative charge

ionic bond

electrostatic attraction between oppositely charged ions in a lattice

• High melting and boiling points

• Don’t conduct

how’s an ionic bond formed

when a metal atom (loses and becomes a cation) and a non metal atom (which gains and becomes and anion)

Explain the formation of ions in ionic compounds (group 1,2,6,7)

Ions are formed through the transfer of electrons between atoms. group 1 and 2 are metals so they lose 1-2 electrons. group 6 and 7 are non metals so they gain 6-7 electrons

using of “ide”

used for compounds of elements formed between two atoms

using of “ate”

used for compounds containing polyatomic ions

(back of the book ions)

describe the structure of an ionic compound

• lattice structure

• regular arrangement of ions

covalent bond

where two atoms share one or more pairs of electrons

• low melting and boiling points

• don’t conduct

USE DIAGRAMS

whats the typical size of small molecules

couple nanmoetres

Giant covalent

Think of diamond

• high melting and boiling points

• won’t dissolve

• won’t conduct

Structure of graphite

• each carbon atom attached to three other carbon atoms

• hexagonal lattice

• held together by strong covalent bonds and the carbon atoms within each layer but the layers themselves are held together by weak forces

Structure of Diamond

• each carbon atom is boned together to four other carbon atoms

• tetrahedral arrangement

• held together by strong covalent bonds

properties of fullerene C60 and graphene

• cage like structures

• semiconducting properties

• two dimensional hexagonal lattice

polymer

a large molecule formed by many identical smaller molecules known as monomers

properties of metals

• malleable

• conduct electricity due to delocalised electrons

dot and cross diagrams

• shows sharing of electrons

• bad at showing 3d arrangement

• bad at showing relative distance

ball and stick diagrams

• good at showing 3d visualisation of structure of atoms

• difficult to interpret

• bad at showing relative distance

2d representations

• simple

• bad at accurately showing 3d geometry of molecules

3d representation

• computer generated molecules

• difficult to understand

calculate relative formula mass give relative atomic mass

what is the relative formula mass of CO2

given the relative atomic mass of carbon 12 and oxygen16 ? (easy question same formula for all)

Answer: 12 + 16 + 16 =44

empirical formulae

empirical formulae = the simplest whole number ratio of each element in a compound

MADR TABLE

conservation of mass

no atoms are created or destroyed in a chemical reaction they just form products

concentration

concentration = mass/volume

mole

(6.02 × 10²³)

moles formula

Mass = MrMoles

Stoichiometry

Give the ratio of ingredients for a equation