unit 1 Flashcards
relative mass of a proton
1
relative mass of a neutron
1
relative mass of an electron
1/2000
relative charge of a proton
+1
relative charge of a neutron
0
relative charge of an electron
-1
define mass number
number of protons + number of neutrons
define atomic number
number of protons
what is the principle quantum number
energy levels are identified by a number, the larger the number of n the further away from the nucleus and higher the energy level it is
what do each shell contain
atomic orbitals
define wave particle duality
electrons can behave like a wave or particle
4 types of orbitals
s p d f
features of s orbital
spherical. holds 2 electrons max
features of p orbital
3d dumbbell shape 6 electrons max
define subshells
a group of the same type of orbital with a shell
(Each new shell gains a new type of sub shell)
max electrons s subshell can hold
2
max electrons p subshell can hold
6
max electrons d subshell can hold
10
max electrons f subshell can hold
14
max electrons in main energy level 1
2
max electrons in main energy level 2
8
max electrons in main energy level 3
18
max electrons in main energy level 4
32
what is Aufbau principle
Start at the lowest energy level (shell) and add electrons one at a time.
Fill each sub level before starting the next
define isotope
atoms of the same element with the same number of protons but different numbers of neutrons
Define ionic bonding
The electrostatic attraction between oppositely charged ions
Define Hunds rule
Fill each orbital with one electron at a time before pairing electrons
define groups
columns on a periodic table
elements in a group have similar properties
define electron transfer
occurs between metals and non metals
in ionic bonding metals electrons and become ions, non metals electrons and become ions
lose, positive
gain, negative
3 properties of ionic bonding
strong electrostatic forces (in all directions between oppositely charged ions)
high melting + boiling points
when melted or dissolved in water ionic compounds can conduct electricity (ions are free to move + carry current)
diamond features
all atoms in the structure are linked by strong covalent bonds
high melting points
each carbon forms 4 covalent bonds so very hard
Doesn’t conduct electricity
Tetrahedral shape
graphite features
each carbon form to 3 others forming layers
layers slide over each other because there no covalent bonds between layers
soft and slippery
1 electron from 1 carbon is delocalised which allows conduction of heat + electricity
define macromolecule
giant covalent bonds
covalent bonding molecules properties
shared pair of electrons
low melting and boiling point (weak intermolecular forces easier to break)
doesn’t conduct electricity (molecules don’t have overall charge, no free electrons or ions)
metallic bonding features
giant structures of atoms in a regular pattern
loose electrons in outer shell (free to move)
‘sea’ of delocalised electrons
Strong electrostatic attraction between negatively charged electrons that holds structure together
how to work out Mr
add mass number of all elements present together
%mass equation
mass of element/mass of compound x 100
%yield equation
amount of product (actual)/max of potential (theoretical) x 100
define empirical formula
simplest whole number ratio
What is a Dative covalent bond
The atoms supplies both the shared pair of electrons to the covalent bond
What is lone pair of electrons
Outer shell pair of electrons this is not involved in chemical bonding
The Of a solution is a measure of how much Is dissolved of .
Concerntrate , solute, per unit, solvent
Concerntration equation
Amount of solvent (moles)/ volume of solute (dm^3)
Mass of solid / volume of liquid
What is solute measured in
Moles (amount)
Volume of solvent is measured in
Dm^3
conc measured in
moldm^3
1 ml to cm
1cm
1000ml to litre
1litre
1000ml to dm^3
1dm^3
What did dimitri Mendeleev do
Arranged elements by atomic weight
Left gaps for missing elements
Elements in the same group have similar properties
What did Henry Moseley do
Arranged period group in order of increasing atomic number (related to atomic mass)
Define periodicity
Variation of properties of elements with changing atomic number
What is First ionisation energy
The energy required to remove one electron from each atom in one mole of atoms in the gaseous state ( from 1 mole of 1+ ions)
Na(g) -> Na(g) + e-
Nuclear charge increases (more attraction) harder to lose electron
What is titration
Neutralisation coloured water to colourless to see conc of solution
