3. Atoms, Elements
and Compounds
Date
0620 RM
3.1 Atomic Structure and the
Periodic Table
3.1 Atomic structure and the Periodic Table
Core
State the relative charges and approximate relative
masses of protons, neutrons and electrons
Define proton number and nucleon number
Use proton number and the simple structure of atoms to explain
the basis of the Periodic Table (see section 9), with special
reference to the elements of proton number 1 to 20
Define isotopes
State the two types of isotopes as being radioactive and
non-radioactive
State one medical and one industrial use of
radioactive isotopes
Describe the build-up of electrons in 'shells' and
understand the significance of the noble gas electronic
structures and of valency electrons (the ideas of the
distribution of electrons in s and p orbitals and in d block
elements are not required.)
(Note: a copy of the Periodic Table, as shown in the Appendix,
will be available in Papers 1, 2 and 3)
Atoms consist of protons, neutrons
and electrons.
Particle
O
proton
neutron
electron
Mass/atomic mass
units
Charge
1
+1
1
O
1/1840 → 0
-|
Proton number /atomic number: number of
protons in an atom
nucleon number: number of protons and neutrons
in an atom
Le relative atomic mass
The periodic table is ordered
by proton number
• columns indicate groups with similar
reactions / properties
• rows are called
periods
grange
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e.g
0580
MA
Isotop
es
Isotopes are atoms of the same element with a
different number of neutrons (same proton number)
12
6
2( 136
13 (14C Radioactive (radioisotope) nucleus is unstable
so it decays to give off
radiation
6
non-radioactive
6
Uses of
radioisotopes:
Cancer treatment (cobalt-60) - radiation
destroys cancerous cells
• Detecting leaks - added to
oil or gas in pipeline
-radiation can be detected with GMtube O
Electron
Electrons
build
up
in
'Shells'
Valency electrons are the
elections in
the outer shell-they dictate
how an
element reacts to bomo Corton
XX
1st shell
holds max.
2 electrons
2nd shell holds max
8 electrons
Noble gases (Group 0) have a full
valence shell - unreactive
3.2 Bonding: the
Structure of Matter
3.2 Bonding: the structure of matter
Core
Describe the differences between elements, mixtures and
compounds, and between metals and non-metals
Describe an alloy, such as brass, as a mixture of a
metal with other elements
O
stosibat camuls.
Looney ballos 9
No.
0620
"
Date
RM.
Element: -contains only one type of atom
od fotsin at Compound: more than one type of
atom chemically bonded
@
atoma bonded in same
ratio
• cannot be separated by
physical means
·Mixture: - can contain any number of
substances in any ratio
• not joined by chemical
bonds nobl
Metals and nonmetals
.
Metal
s
• readily conduct
electricity & heat
•Mostly malleable and ductile
s
to
H
of Mibod
Non-metal
・do not conduct
electricity and heat ・
usually brittle
normally shiny! noitsoil. look dull
when solid
0
tend to have high
density
0
higher m.p and
b.p
• low
density
•form positive
ions
• usually form basic
oxide,
low melting
points
• form negative
ions
•usually form
acidic oxides
Alloys are mixtures of metals with
other elements.
AGM
Custom
3.2 (a) Ions and Ionic Bonds
solo as
•
3.2(a)
3.2 (a) lons and ionic bonds
Core
Describe the formation of ions by electron loss
or gain
Describe the formation of ionic bonds between elements from
Groups I and VII
Knot Tons are
formed by
- electron loss electron gain
=
Supplement
Describe the formation of ionic bonds
between metallic and non-metallic
elements
Describe the lattice structure of ionic
compounds as a regular arrangement of
alternating positive and negative ions
electron
transfer
positive
ion
had tas Love)
negative ion bomot of
nos
eting
Tonic bonds only form between a metal and a
non-metal, where
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green
range
0.00
sodium
atom
the metal loves elections (becoming positive) and
the non-metal gains elections (becoming
negative)
out sho
Tonic bonding between Group I
and Group VII.
Sodium loses election, chlorine
gains electron
sutxi M
chlorine atom
sodium
ion
chlorine ion
Na
election
Cl
Na
transfers
O
slit such bow both have full
outer shell
2, 8, 1 Hool
for
Due to their electrostatic attraction, the two ions are
attracted to
each o
+ her list wall
Lattice structure on t
white hos min
love w
dad
of brot
4.01 isdeld
cabixo sical mot
ullover
Many ions group together, forming a giant
ionic lattice with a regular arrangement of
alternating positive and negative ions. 3.2(0)
Molecules and Covalent Bondso
3.2 (b) Molecules and covalent bonds
Core
Describe the formation of single covalent bonds in H2, CL,
H2O, CH, and HCl as the sharing of pairs of electrons
leading to the noble gas configuration Describe the
differences in volatility, solubility and electrical conductivity
between ionic and covalent compounds
Supplement
Describe the electron arrangement in more
complex covalent molecules such as N2,
C2H, CH,OH and CO
Covalent bonds are formed when atoms share
electrons.
can be formed between atoms of the jame non-me tal can
be formed between atoms of different nonmetals. The bonded atoms form units - molecules
Simple molecular compounds have weak
inter-molecule bonds, strong intra-molecule
covalent bonds.
No.
0620
Date RM.
Formation of single covalent
bonds
H +
H2
HAH
sharing elections
lead, to gas
configuration
noble
two single covalent
bonds
More complex
covalent molecules
HAC
H
CH4
ON2
EN
ON
three pairs
of
XN) N⚫ shared
electron
-triple bond
G2 H
4
H
N =N
H
H
Hon H
(=C
.
CO
2
CH2O
H
H
Xo
HOC
H
0=C=0
-double bond, 0° -linear
H
X
CH
H-C-O-H
H
Comparing ionic and simple
molecular compounds
IONIC
MOLECULAR
High m.p & b.p-strong attractions • Low
m.p fb.p -weak attractions
•are not volatile
• conduct electricity
when liquid -presence
of charged particles
• soluble in
water 1• hard
are volatile do not conduct electricity - no
Tcharged particles insoluble
in water
grange
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32(c)
Macromolecules
3.2 (c) Macromolecules
Core
Describe the giant covalent structures of graphite and diamond
Relate their structures to the use of graphite as a
lubricant and of diamond in cutting
Supplement
Describe the macromolecular structure of
silicon(IV) oxide (silicon dioxide)
Describe the similarity in properties
between diamond and silicon(IV) oxide,
related to their structures
Graphit
e
Carbon a
tom
electron
strong covalent
bonds
-weak
forces
1. Each carbon atom bonded with three
others.
There is a free electron
• Covalent bond, within
layers are strong
• Weak forces
between layers
•
O
Used as a lubricant - lagers
can slide
• Used as electrodes - can
conduct electricity due
Each carbon atom becomes part of a flat hexagonal
ring to delocalbed electron
Diamond
strong
covalent bonds
Each carbon atom forms a tetrahedron with
four other carbon atoms.
.
• Each carbon atom joined with
four others with strong covalent
bonds, forming a giant covalent
lattice
• All bond, are identical, no weak
bonds
• Used in cutting tools - hardest
natural O substance as
0
Used in jewellery - shiny and
translucent
Silicon (IV) oxide
(silicon dioxide)
antic Similar structure to diamond,
tetrahedral in shape.
• each silicon atom covalently bonded
with four oxygens
• each oxygen bonded with two
silicons
Similar
properties to
diamond:
• high melting point and
very hard
non-conductor of electricity and
insoluble in water Used in sandpaper
and to line furnaces
silicon
охудет
3.2(d) Metallic
Bonding famous
metal
107
electron
3.2 (d) Metallic bonding
Supplement
Describe metallic bonding as a lattice of positive ions in a 'sea of electrons' and use this to describe the electrical
conductivity and malleability of metals
No.
0620
Date RM.
In metallic bonding, the valence electrons leave the
metal atoms, giving stable metal ions with full
outer shells.
+
+
+
Giant lattice of positive metal
ions in a sea of delocalised
electrons
• Bonds are strong- electrostatic attraction
between positive ions and
negative electron s
Explaining metal
properties.
•
High
• High mp and b.p- strong electrostatic
attraction therefore strong bonds
• Electrical conductors -delocalised electrons carry charge
through metal Thermal conductor) -delocalised
electrons carry thermal energy through metal
Malleable and ductile - layers of ions can slide over
eachother
O
green
range
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