SAC Revision Flashcards
What is an element?.
pure substance that only contains one type of element.
What is an Isotope?
Variation of an element with the same atomic number/number of protons, but different mass number/number of neutrons
What is an ion?
an atom that has lost or gained electrons to become a charged particle (protons =/ electrons)
What is atomic number?
number of protons in an atoms nucleus, the atomic number is the top number on a period box
What is mass number?
mass of an atom, is equal to protons + neutrons
In what context are the amount of protons and electrons the same?
in a particle with no charge, particle/atom that hasn’t lost/gained electrons
What are the 5 the periodic trends?
McCAFE
Metallic Character, Core Charge, Atomic Radius, First Ionisation Energy and Electronegativity
What is Metallic Character and how does it increase?
degree in which an element is shiny and conducts electricity
increases ↙
What is Core Charge and how does it increase?
The pull of the positive nucleus on valence electrons
increases ⭢
How is core charge calculated?
protons - inner shell electrons = core charge
What is Atomic Radius and how does it increase?
the distance from the centre of an atom to the valence electrons
increases ↙
What is First Ionisation Energy and how does it increase?
the energy required to remove the first valence electron
increases ↗
What is Electronegativity and how does it increase?
ability of an element to attract shared electrons towards itself
increases ↗
What is covalent bonding?
sharing of electrons between non-metals
What is the Lewis Structure?
digram representing bonding with dots and crosses
What is Structural Formula?
diagram representing bonds with lines
What are the 4 molecular shapes?
linear, bent, pyramidal and tetrahedral
What does the linear shape look like?
o-o
What does the bent shape look like?
o o
\ /
o
What does the pyramidal shape look like?
. o
/ | \
o o o
What does the tetrahedral shape look like?
. o
|
. o
/ | \
o o o
What is the VSEPR theory?
theory that states that electrons pairs repel each other so they will move as far apart as possible, thus creating different shapes
What is polarity?
property of having one partial positive and one partial negative charge
What is a polar molecule?
a molecule that displays polarity and has a partial positive and negative charge
What is a non-polar molecule?
a molecule that has no overall charge
What is the relation between polarity and molecular shape?
Symmetrical molecules tend to be non-polar and asymmetrical molecules tend to be polar
due to equal charges on both sides cancelling each other out