Y13 Chem mock Flashcards
Why are do isotopes have similar chemical properties
Same electron configuration which affects the chemical properties of the atoms
Why do isotopes have different physical properties
due to the differing masses of the atoms they can have different densities
What did jj thompson add to the understanding of chemistry
The atom contains negatively charged particles called electrons, devised the plum pudding model(positive charge with small negative charges dotted)
What did rutherford add to the understanding of chemistry
He fired alpha particles at a thin sheet of gold most of the particles went straight through which suggests the atom isn’t entirely positive some of them were reflected. Suggested nuclear model positive nucleus with clouds of electrons that float around it
What modifications did rutherford add
Realised that nucleus had positive charge that varied between atoms, determined existence of protons
What did james chadwick discover
Existence of neutrons
What is relative atomic mass
Ar is the weighted mean mass of an element compared to 1/12 the mass of an atom of C-12
What is the relative isotopic mass
Mass of an atom of an isotope compared to 1/12 the mass of c12
What is molar mass
The mass of one mole of something (“g mol-1)
What is the gas volume equation
number of moles = volume in dm3/24
what is room temp and pressure
298k, 100kPa
Ideal gas equation and units
pV = nRT
p = Pa kPa to Pa *1000
V= dm3 cm to dm3 /1000 dm3 to m3 /1000
n= moles
R=8.314
T= K *c + 273
concentration equation
moles= conc * volume (dm3)
what is the empirical formula
smallest number ratio of atoms in a com pound
Important ions
Nitrate- No3-
Carbonate- CO32-
SO42-
OH-
NH4+
What are acids, main ones
proton donors
HCL
H2SO4
HNO3(nitric)
CH3COOH(ethanoic acid
what are bases, common bases
proton acceptors
NaOH
KOH
NH3
What is the reaction between ammonia and H20
NH3 + H20 -> NH4+ + OH-
reversible
Strong bases/ acids
HCL fully dissociates in water, and nearly all the H+ ions are released
weak bases/ acids
backward reaction favoured so small amoutns of acid dissociates in water and few H+ ions are released
Acid + Base ->
Salt + Water
Metal + Acid
Salt + Hydrogen
Metal oxide + Acid
Salt + Water
Metal hydroxide + Acid
Salt + Water
What is the principal quantum number
energy levels in which electrons lie(shells)
What are subshells
Further division of the shells
What are orbitals
Areas of space in which electrons can be found(cloud) can only hold up to 2 electrons
What main property of electron
quantum property of spin, they spin in opposite directions they also repel each other to an extent
What is a giant ionic lattice
repeating regular structure of ironically bonded atoms
Behaviours of ionic compounds
conductivity in molten/dissolved because ions can move and carry charge
high melting and boiling points ionic compounds are held together by lattice which has strong electrostatic forces
soluability can dissolve in water due to charges hydrogen bonds can form
What is a dative bond
when an atom donates 2 electrons on its own in a covalent bond
What are the special cases for covalent bonds
Boron trifluoride (6 electron in outer shell)
Sulphur hexafluoride expands the octet and has 12 electrons in its outer shell
What is average bond enthalpy
the energy required to break a covalent bond
Linear shape
2 bonding pairs no lone pairs(180)
trigonal planar
3 bonding pairs (120)
tetrahedral
4 bonding pairs(109.5)
trigonal pyramidal
3 bonding pairs 1 lone pair (107)
non-linear
2 bonding pairs 2 lone pairs(104.5)
trigonal pyramidal
5 bonding pairs 120 and 90
octahedral
6 boning pairs(90)
