AICE Chemistry AS Syllibus Line by Line

Electron

negatively charged particle found in orbitals outside the nuclus of an atom, neglibile weight (1/1840)

Proton

positivly charged particle in the neclus of an atom (weight 1)

Neutron

uncharged particle in the nucleus of an atom (weight 1)

Atomic number

the number of protons in the nuclus of an atom

aka proton number

subscript of isotopic symbols

Isotope

atoms of the same element with different mass numbers

mass number

Number of protons and neutrons in an atiom

aka neuclon number

Same number of electrons

Why do isotopes have the same chemical properties?S

different number of neutrons

Why do isotopes have different physical properties?

s orbital

circle

one orbital

2 electrons

p orbital

infinity symbol (dumbell)

3 orbitals

6 electrons

d orbital

flower shape (daisy)

5 orbitals

10 electrons

Electron configuration

a way of represnting the arrangement of electrons in an atom showing the principle quantium shells, sub-shells, and number of electrons present

Free radical

a species with one or more unpaired electron

homolvtic fussion

How is a free radical formed?

Aufbau Principle

states that each electron occupies the lowest energy orbital available

Hands Rule

electrons are only paired wgen there are no more empty orbitals availible within a subshell, in which case the spins are oppisite to minimize repulsion

Chromium and Copper

What two elements are the exception to the filling rule, and have one s electron moved to a p orbital

first ionization energy

The energy needed to remove the first mole of electrons from one mole of atoms of an element in the gaseous state to form one mole of gaseous ions

Ionization energy equations

all atoms are in a gaseous state

you show that the products are one mole of electrons and one mole of positivly charged atoms

Successive Ionization Energies

energies required in each step to remove the next electron from a gaseous atom

Ionization energy trends

increase across a period and decrease down a group

Four factors of first ionization energy

size of neuclear charge

distance of outer electrons from the neuclus

shielding effect of inner electrons

spin pair repulsion

Sheilding

the ability of inner shell electrons to reduce the effect of the neuclear charge on outer shell electrons

Atomic orbital

regions of space outside the nuclus that can be occupied by a maxium of 2 electrons

Atomic radius

the covalent atomic radius is half the distance between the nuclei of 2 covalently boneded atoms of the same type (increases down a group, decreases across a period)

Unified atomic mass unit

1/12 of the mass of a carbon-12 atom

realitive atomic mass

the weighted average mass of atoms in a given sample of an element compared to the value of the inified atomic mass unit

(mass\*realitive abundance)/100=amus

realitive isotopic mass

the mass of a particular atom of an isotope compared to the value of a unified atomic mass unit

Realitive molecular mass

the weighted average mass of a molecule in a given sample pf that molecule compared to the value of the unified atomic mass unit

Realitive formula mass

the weighted average mass of one formula unit compared to the value of the unified atomic mass unit

mole

the amount of substance which contains 6.02x10^23 specified particles

Avogodro constant

6.02x10^23

Emperical formula

the simplest whole number ratio of element present in one mole of molecule or formula unit of the compound

Molecular formula

A formula that shows the number and type of atoms of each element present in a molecule

Anhydrous

containing no water of crystiallization

hydrated

compound which contains a definite number of moles of water in their structure

Water of crystallisation

a specific number of moles of water associated with a crystal structure

Molar mass

mass of substance in grams/mass of one mole

Percetn Yeild

(actual/expected)x100

One mole of gas at standard conditions

24 dm^3

concentration is

moles over voles

Limiting Reactant

the reactant not in excess

Excess Reactant

the reactant that has the number of moles in excess

mass given in g/moles

How do you find the stoich of a problem

percent composition by mass

(atomic mass x number of moles in the compund)/molar mass of compund

Solute

a substance which dissolves in a sovlent to form a solution

Solvent

a substance which dissolves a solute to form a solution

Oxidation number

a number given to an atom or ion in a compund that describes how oxidized or reduced it is

Electronegitivity

the power of an atom to attact electrons to itself

Ionic bonding

the electrostatic attraction between oppositely charged ions

Describe how ions are formed

When the negitivly charged atom (metals) loses an elctron to a positivly chared atom (non metals)

Metalic bonding

the electrostatic attraction between positive metal ions and a sea of delocalized electrons

Covalent bonding

electrostatic attraction between the nuclei of two atoms and a shared pair of electrons

what period of elements can expand thier octet

period 3 ex. SO2, PCl5, SF6

Lone pairs

pairs of electrons in the outer shell of an atom that are not involved in bonding

Co-ordinte bond (aka dative bond)

the sharing of a pait of electrons between two atoms where both the electrons in the bond come from the same atom ex. NH4, Al2Cl6

the direct overlap of orbitals between the bonding atoms

How are sigma bonds formed

How are pie bonds formed

the sideways overlap of adjacent p orbitals above and below the sigma bond

Hybridisation

the mixing of atomic orbitals to from covlane bonds

Bond Energy

the energy required to break one mole of a particular covalnet bond in the gaseous state

Bond length

the internucler distance of two clvalently bonded atoms

What makes bond energy higher

more bonds and less bond length

Trigional Planar

120 degrees

BF3

Linear

180 degrees

CO2

Tetrahedral

109\.5 degrees

CH4

Pryamidal

107 degrees

NH3

Non-linear

104\.5 degrees

H2O

Octahedral

90 degrees

SF6

Trigonal bipryamidal

120 and 90 degrees

PF5

Hydrogen bonding

when hydrogen is bonded to F,O,N and there is a lone pair of electrons to attract the positvly charged hydrogen to

Properties of hydrogen bonds

high boiling point

high surface tenstion

less dense in solid form

Polar bonds

the electron pair in the bond is drawn towars the atom with the larger electronegativity, making one ens slightly positive

Bond polarity

tbe partial sperperation of charge when two different atoms are joind by a covalent bond

Vander Waals Forces

the intermolecular forces between molecular entities other than those due to bond formation

Instantaneious dipole dipole forces

weakest intermolecualr force

temperaroy instintaneous dipoles in polar and non-polar moelcules

london dispersion forces

one molecule brings about an attractive or repulsive affect on another

Perminate Dipole Dipole Forces

attractive intermolecular forces which result from permanent dipoles in molecules

perminate dipole dipole

Why type of force is hydrogen bonding

know how to use dot and cross diagrams idot

please

gas molecules coliding with the sides of the container

What causes pressue in gas

Elements of Ideal gases

no paritcle volume

no intermolcualar forces

PV=Nrt

P=pressure

V= volume

N=moles of substance

R= ideal gas constant (8.31)

T= temp

stopped at 4.2