ATOMIC STRUCTURE & THE PERIODIC
TABLE
ATOMS, ELEMENTS & COMPOUNDS
- An atom is the smallest part of an element that can exist.
- Elements are made up of one type of atom, and there
about 100 of them found on the Periodic Table.
- Compounds are made when two or more elements are
chemically bonded together.
MIXTURES
- Mixtures are two or more elements or compounds that are
not chemically bonded together.
- Filtration separates an insoluble solid and a liquid. A
mixture gets poured into the funnel and the solid gets stuck
on the filter paper as residue, but the liquid filters through,
called the filtrate, and is collected in a conical flask.
- Crystallization separates a salt solution. The solution is
heated using a bunsen burner in an evaporating dish atop a
tripod, where the solvent evaporates and crystals form.
- Distillation separates solvents from a solution. The
mixture is heated over a bunsen burner until one
evaporates, then it condenses in a liebig condenser before
being collected as a liquid in a beaker.
DEVELOPMENT OF ATOMIC MODEL
- Originally thought to be a tiny sphere of matter that is
indivisible.
- Thomson developed the Plum Pudding model to show the
atom is a sphere of positive charge with negative electrons
embedded in it.
- Rutherford conducted an experiment where he fired alpha
particles at a thin sheet of gold, and concluded positive
, charge in an atom was in the centre which caused some
particles to scatter, and that the atom is mostly empty
space as most particles passed through the atom.
- Bohr adapted Rutherford's model and concluded electrons
orbited at set distances from the nucleus, known as shells.
- Finally, Chadwick provided evidence for the neutron found
in the nucleus which is now the modern model.
RELATIVE CHARGES OF SUBATOMIC PARTICLES
- Protons have a +1 charge, neutrons have no charge and
electrons have -1 charge.
- Atoms have the same number of protons and electrons so
have an overall neutral charge.
- Atomic number is the number of protons in an atom, and
atomic mass is the number of protons and neutrons.
SIZE AND MASS OF ATOMS
- Atoms have a radius of 1 x 10 m, and the radius of the
-10
nucleus is 10,000x smaller, with mass concentrated in the
nucleus.
- The relative mass of protons and neutrons are 1, and the
relative mass of electrons is very small.
- Isotopes are atoms of the same element with a different
number of neutrons.
RELATIVE ATOMIC MASS
- Relative atomic mass is an average value that takes
account of the abundance of isotopes in an element.
- Ar is calculated by (% of Isotope A x Mass of Isotope A) +
(% of Isotope B x Mass of Isotope B)/100.
ELECTRONIC STRUCTURE
- Electrons occupy the lowest available energy levels and
hold 2 in the first shell and 8 in all other shells.
, PERIODIC TABLE
- Elements are arranged in the Periodic Table in order of
atomic number, with elements of similar properties in
columns known as groups. Elements in the same group have
the same number of outer shell electrons.
- Periods in the periodic table are the vertical columns of
elements.
DEVELOPMENT OF PERIODIC TABLE
- Dalton arranged elements based on atomic weight,
Dobereiner grouped chemicals in triads with similar
chemical properties, and Newlands realised every 8th
element had similar properties, but these early models were
incomplete and flawed.
- Mendleev solved these flawed models by lining up
elements in increasing atomic weight and positioned similar
property elements in columns, left gaps for undiscovered
elements, and rearranged the order of some elements based
on atomic weights.
METALS AND NON METALS
- Elements that form positive ions are metals, and elements
that form negative ions are non-metals.
- Metals are found on the left of the Periodic Table, and
non-metals on the right.
- Metals are shiny, solid at room temperature, have high
melting and boiling points, are malleable, ductile and are
good conductors.
- Non-metals are dull, gases at room temperature, have low
melting and boiling points, are brittle, non-ductile and poor
conductors.
GROUP ZERO
, - Called the Noble Gases and are unreactive due to having
full outer shells, with boiling point increasing down the
group.
- The Noble Gases are inert, non-flammable, colourless and
odourless, exist as a single atom with weak intermolecular
forces and all have low boiling points.
GROUP ONE
- Called the Alkali Metals and have one outer shell electron.
They are silvery solids, highly reactive, soft and can be cut
with a knife, less dense but increases down the group and
have a decreasing melting and boiling point down the
group.
- Reactivity increases down the group as a larger nuclear
radius results in the outer electron being further from the
nucleus, so it is more easily lost due to being less attracted
to the nucleus.
- When reacting with oxygen, alkali metals form metal
oxides. Lithium forms a red flame and white solid, sodium
forms an orange flame and white solid, and potassium
forms a lilac flame.
- When reacting with water, they form a metal hydroxide
and hydrogen gas, being more vigorous and more rapid
fizzing down the group.
- When reacting with chlorine, they form metal chlorides,
becoming more vigorous down the group.
GROUP SEVEN
- Called the Halogens and have seven outer shell electrons.
They exist as diatomic molecules, are coloured vapours,
have low melting and boiling points, are brittle when solid,
non-ductile, and poor conductors.
TABLE
ATOMS, ELEMENTS & COMPOUNDS
- An atom is the smallest part of an element that can exist.
- Elements are made up of one type of atom, and there
about 100 of them found on the Periodic Table.
- Compounds are made when two or more elements are
chemically bonded together.
MIXTURES
- Mixtures are two or more elements or compounds that are
not chemically bonded together.
- Filtration separates an insoluble solid and a liquid. A
mixture gets poured into the funnel and the solid gets stuck
on the filter paper as residue, but the liquid filters through,
called the filtrate, and is collected in a conical flask.
- Crystallization separates a salt solution. The solution is
heated using a bunsen burner in an evaporating dish atop a
tripod, where the solvent evaporates and crystals form.
- Distillation separates solvents from a solution. The
mixture is heated over a bunsen burner until one
evaporates, then it condenses in a liebig condenser before
being collected as a liquid in a beaker.
DEVELOPMENT OF ATOMIC MODEL
- Originally thought to be a tiny sphere of matter that is
indivisible.
- Thomson developed the Plum Pudding model to show the
atom is a sphere of positive charge with negative electrons
embedded in it.
- Rutherford conducted an experiment where he fired alpha
particles at a thin sheet of gold, and concluded positive
, charge in an atom was in the centre which caused some
particles to scatter, and that the atom is mostly empty
space as most particles passed through the atom.
- Bohr adapted Rutherford's model and concluded electrons
orbited at set distances from the nucleus, known as shells.
- Finally, Chadwick provided evidence for the neutron found
in the nucleus which is now the modern model.
RELATIVE CHARGES OF SUBATOMIC PARTICLES
- Protons have a +1 charge, neutrons have no charge and
electrons have -1 charge.
- Atoms have the same number of protons and electrons so
have an overall neutral charge.
- Atomic number is the number of protons in an atom, and
atomic mass is the number of protons and neutrons.
SIZE AND MASS OF ATOMS
- Atoms have a radius of 1 x 10 m, and the radius of the
-10
nucleus is 10,000x smaller, with mass concentrated in the
nucleus.
- The relative mass of protons and neutrons are 1, and the
relative mass of electrons is very small.
- Isotopes are atoms of the same element with a different
number of neutrons.
RELATIVE ATOMIC MASS
- Relative atomic mass is an average value that takes
account of the abundance of isotopes in an element.
- Ar is calculated by (% of Isotope A x Mass of Isotope A) +
(% of Isotope B x Mass of Isotope B)/100.
ELECTRONIC STRUCTURE
- Electrons occupy the lowest available energy levels and
hold 2 in the first shell and 8 in all other shells.
, PERIODIC TABLE
- Elements are arranged in the Periodic Table in order of
atomic number, with elements of similar properties in
columns known as groups. Elements in the same group have
the same number of outer shell electrons.
- Periods in the periodic table are the vertical columns of
elements.
DEVELOPMENT OF PERIODIC TABLE
- Dalton arranged elements based on atomic weight,
Dobereiner grouped chemicals in triads with similar
chemical properties, and Newlands realised every 8th
element had similar properties, but these early models were
incomplete and flawed.
- Mendleev solved these flawed models by lining up
elements in increasing atomic weight and positioned similar
property elements in columns, left gaps for undiscovered
elements, and rearranged the order of some elements based
on atomic weights.
METALS AND NON METALS
- Elements that form positive ions are metals, and elements
that form negative ions are non-metals.
- Metals are found on the left of the Periodic Table, and
non-metals on the right.
- Metals are shiny, solid at room temperature, have high
melting and boiling points, are malleable, ductile and are
good conductors.
- Non-metals are dull, gases at room temperature, have low
melting and boiling points, are brittle, non-ductile and poor
conductors.
GROUP ZERO
, - Called the Noble Gases and are unreactive due to having
full outer shells, with boiling point increasing down the
group.
- The Noble Gases are inert, non-flammable, colourless and
odourless, exist as a single atom with weak intermolecular
forces and all have low boiling points.
GROUP ONE
- Called the Alkali Metals and have one outer shell electron.
They are silvery solids, highly reactive, soft and can be cut
with a knife, less dense but increases down the group and
have a decreasing melting and boiling point down the
group.
- Reactivity increases down the group as a larger nuclear
radius results in the outer electron being further from the
nucleus, so it is more easily lost due to being less attracted
to the nucleus.
- When reacting with oxygen, alkali metals form metal
oxides. Lithium forms a red flame and white solid, sodium
forms an orange flame and white solid, and potassium
forms a lilac flame.
- When reacting with water, they form a metal hydroxide
and hydrogen gas, being more vigorous and more rapid
fizzing down the group.
- When reacting with chlorine, they form metal chlorides,
becoming more vigorous down the group.
GROUP SEVEN
- Called the Halogens and have seven outer shell electrons.
They exist as diatomic molecules, are coloured vapours,
have low melting and boiling points, are brittle when solid,
non-ductile, and poor conductors.
