Chemistry Flashcards
What is the atomic number ?
the number of protons in the atom
What is the atomic mass?
The number of protons + number of neutrons
Electron configuration: What is present in n=1, 2, 3 and 4.?
n=1: 2 electrons max in 1 subshell type 1s2
n=2: 8 electrons max in 2 subshell types 2s2 2p6
n=3: 18 electrons max in 3 subshell types 3s2 3p6 3d10
n=4: 32 electrons max in 4 subshell types 4s2 4p6 4d10 4f14
What is present in group 1, 2, 13, 14, 15, 16, 17, 18 of the periodic table ?
1= alkali metals e.g. lithium and sodium 2= alkaline earth metals e.g. magnesium and calcium 13= B and Al 14= C, Si 15= N, P 16= O, S 17= halogens, Fluorine, chlorine, bromine 18= noble gases, heliu
What is an ionic bond?
atoms exchange electrons to give ions that form strong electrostatic bonds.
bond strength increases with increasing charge and smaller ions
What are ionic crystals?
inorganic salts with giant lattice structures
What are strong ionic bonds?
solid at room temp with high melting and boiling points
What are ionic solutions?
conduct electricity when molten or dissolved in water
What are covalent bonds?
atoms share one or more electron pairs to achieve a full outer shell
Define: molecular covalency
number of shared electron pairs
What are metallic bonds?
atoms are packed together tightly, surrounded by a sea of electrons (de-localised)
What are the properties of a metallic bond?
- most have high melting points (strong bonds)
- good electrical and thermal conductivity (highly mobile outer electrons)
- high strength, especially when alloyed with other metals
What is electronegativity?
this is the ability of atoms to attract electrons - concept links ionic and covalent bonding
What does a large difference, >2, in electronegativity indicate?
favours ionic bonds
What does similar electronegativities indicate ?
favour covalent bonds
What does intermediate electronegativities indicate?
form polar compounds that display both types of bonding
Define mole:
one mole of any substance contains 6.022x 1023 particles of the substance
What are the 4 neutralisation chemical reactions ?
1) acid + base goes to metal salt + water
2) acid + carbonate/hydrogen carbonate goes to metal salt + water + carbon dioxide
3) acid + ammonia goes to ammonium salt + water
4) acid + metal goes to metal salt + hydrogen
OILRIG:
Oxidation is LOSS = add oxygen/remove hydrogen/loss of electrons
Reduction is GAIN = remove oxygen/add hydrogen/gain of electrons
What is a combustion reaction ?
oxidation of each element in the compound
What is a composition reaction?
A + B goes to AB
What is a decomposition reaction?
AB goes to A + B
What is a dissociation reaction ?
AB goes to A+ + B-
What is a substitution reaction ?
swap an atom, ion or group in a molecule
What is a hydrolysis reaction ?
add water molecule
What is a condensation reaction ?
remove water molecules
What is a 1M concentration?
1 mole of solute in 1 litre of solution
What is another way of expressing pH?
-log10 molecules H+/L
How is rate represented in reaction rates?
rate= k[A]x[B]y
How is a zero order reaction represented?
x+y=0 rate =k (k is the rate constant)