Topic 1 & 3 Flashcards
(45 cards)
Nucleon number
Atomic number
N (mass):
- num of protons and neutron
- in the nucleus of one atom of an element
A (proton):
- the number of protons
- in the nucleus of one atom of an element
Proton Relative mass, relative charge
Neutron
Electron
Relative mass, relative charge
P 1, +1
N 1, 0
E 1/2000 (0.0005), -1
Isotope definition (2 m)
- ATOMS with the same num of protons/atomic num
- but different num of neutrons/mass num
Relative Atomic mass
definition (3 m)
(Ar)
- the avg mass of all the isotopes of an element
- taking into account their percentage abundance,
- relative to carbon-12
Calculating Ar
(mass num x % abundance) + … / 100
Period num & group num
period num = num of electron shells
group num = num of electrons on outer shell
Group 1
Alkali metals - they all react in a similar way as they all have 1 electron in their outer shell.
Group 2
Alkaline earth metals - react in a similar way:
2 electrons
in outer shell
Group 7
The Halogens - react in a similar way
7 electrons
in outer shell
Group 8/0
The Noble Gases
unreactive/ inert:
they have a full outer electron shell.
Properties of metals (6)
- malleable(can change shape easily)
- good conductors of heat and electricity (electrons are free to move)
- sonorous (make a sound when hit)
shiny
ductile (stretch)
high melting point - A lot of heat energy is needed to overcome forces and break strong metallic bonds in giant metallic structures
properties of non-metals (5)
dull brittle poor conductors - fixed electrons not sonorous low melting point - weak intermolecular forces between the molecules
Ionic bonding
(metal + non-metal)
- The electrostatic force of attraction between oppositely charged
- ions
Describe, in terms of electrons, how an ionic bond in [sodium chloride] is formed. (3 m )
- electron transfer
- from sodium to chlorine
- sodium has lost 1 electron (oxidised) and chlorine has gained 1 electron(reduced).
Relative Molecular Mass definition
(Mr)
sum of the relative atomic masses.
Element definition
Substance that cannot be broken down into anything simpler/
substance containing atoms with the same atomic number or proton number
Ionic bonding
structure & physical properties: conductivity and melting point
Structure: giant crystal lattice
(continuous ions) (regular, pattern of oppositely charged ions)
Properties:
- High melting point (solids at room temp)
- requires large amount of energy to overcome
- the STRONG
- electrostatic forces of attraction between oppositely charged ions. - Can conduct only when MOLTEN or in SOLUTION(dissolved)
- ions
- are free to move
Which has the highest melting point out of NaCl and MgO? (3 marks)
- MgO has the higher melting point
- greater charges of the Mg2+ ion and O2- ion relative the Na+ and Cl-
- therefore stronger forces of attraction between ions in MgO
Covalent Bonding definition (2 m)
The electrostatic force of attraction between
- a shared pair of electrons and
- the positively charged nucleus of EACH ATOM
Molecule definition (2 m)
- a discrete number of atoms
- covalently bonded
Properties of covalent molecules: structure, m & b points, conductivity
simple molecular structure (except diamond..etc)
(simple = discrete number of atoms molecular = atoms covalently bonded)
Low m & b points:
- weak
- intermolecular forces of attraction
- require little energy to overcome
Do NOT conduct - no charged particles that are free to move
Solubility and Volatility of ionic and covalent compounds, monatomic, simple molecular, metallic
Volatility (A substance capable of readily changing from a solid or liquid form to a vapour)
All insoluble except ionic Ionic - soluble, non-volatile (strong ionic bonds) Covalent - insoluble, volatile Monatomic - insoluble Simple molecular - insoluble Metallic - insoluble (reacts with water)
Allotrope definition
different forms of the same element
Diamond structure
C (s)
- tetrahedral arrangement around each carbon
- giant covalent structure
- each carbon is covalently bonded to 4 others
