P1 1 Atomic Structure/ Periodic Table Flashcards
state the product made from the reaction: METAL + NON-METAL + OXYGEN
METAL NON-METAL(-ate)
describe the difference between simple and fractional distillation
- simple - used to obtain the solvent from a solution (water from salt) or two liquids with different boiling points (water from ethanol)
- fractional - used to separate one liquid from a complex mixture with diff boiling points (fractions in crude oil)
describe distillation
- mixture is heated until the substance with the lowest boiling point boils+ turns into a gas
- gas enters the condenser+ condenses into a liquid, pure substance enters the beaker
- (fractional): fractionating column stops other substances from being extracted - will condense before reaching the condenser+ run back down into the flask
name processes to separate mixtures (5)
- filtration (insoluble solids from liquids, sand from water)
- evaporation+ crystallisation (salt from a solution)
- chromatography (different coloured dyes in ink)
- simple distillation (water from salt, water from ethanol)
- fractional distillation (fractions in crude oil)
why does the mass of the products sometimes appear to decrease or increase
- mass decrease - a gas is formed which escapes the container/ system into the surroundings
- mass increase - atoms from a gas in the atmosphere have been added
describe Dalton’s atomic model
atoms are tiny, solid, indivisible spheres
describe Thompson’s atomic model
plum pudding - a ball of positive charge with negative electrons in it
describe Rutherford’s atomic model
nuclear model - a nucleus with positive charge, electrons that orbit, empty space in between (from alpha particle scattering experiment)
describe Bohr’s atomic model
planetary model - electrons orbit in shells at fixed distances/fixed energy levels from the nucleus, empty space between
describe Chadwick’s atomic model
atomic model- nucleus contains positive protons and neutrons with no charge, electrons orbit nucleus at fixed distances, empty space between (discovered neutrons)
state the order of scientists+ their atomic models
DON’T Dalton - ball
TRY TO Thompson - plum pudding - electrons
REMEMBER Rutherford - nuclear - protons in nucleus
BRILLIANT Bohr - planetary - electrons orbit in shells
CHEMISTS Chadwick - atomic - neutrons in nucleus
describe an atom
- nucleus containing protons+ neutrons - almost all the atom’s mass is concentrated here
- electrons orbit in shells at fixed distances from the nucleus
- no overall electric charge/ neutral - contain an equal no. protons+ electrons
describe the old Periodic table (who made it/ why it was good/ why it was wrong)
- created by Mendeleev in 1869
- elements were placed in order of atomic weight and grouped according to chemical properties
-> modern periodic table is ordered by atomic number: more accurate as atomic weight varies in isotopes - he predicted the existence of undiscovered elements+ left gaps in the table
describe properties of group 0 elements and reactivity
noble gases: helium, neon, argon, xenon
* full outer shells so don’t need to gain/lose electrons - therefore unreactive and exist as single atoms
* boiling points increase down the group
* low boiling points - gases at room temp - weak intermolecular forces
* colourless/odourless
describe properties and reactivity of group 1 elements
alkali metals: lithium, sodium, potassium, rubidium
* one electron in outer shell
* they react with oxygen (to form oxides), chlorine (to form chlorides), water (to form hydroxides)
* lower densities (than most metals)
* lower boiling points
* form compounds that are soluble white solids
* form positive ions with +1 charge
* soft+ malleable
* often stored in oil to stop them reacting with oxygen+ water vapour in air
describe why reactivity increases down group 1 (alkali metals)
- need to lose one electron to form full outer shell
- as you go down the group the elements have more shells:
increased distance between nucleus+outer electron so decreases electrostatic attraction between electron+nucleus protons;
increased shielding effect - more inner electrons shield outer electron from electrostatic force - therefore less electrostatic force = outer electron is more easily lost = reactivity increases down the group
- therefore boiling points decrease down the group
describe properties and reactivity of group 7 elements
halogens: fluorine, chlorine, bromine, iodine
* need to gain one electron to form full outer shell
* low boiling points
* form compounds that are soluble white solids
* form negative ions with -1 charge
* coloured
* toxic
* higher molecular masses as you move down group
* react with metals to form the ionic compound halide salt
* a more reactive halogen can displace a less reactive halogen from a salt solution
describe why reactivity decreases down group 7 (halogens)
halogens: fluorine, chlorine, bromine
* need to gain one electron to form full outer shell
* as you go down the group the elements have more shells:
increased distance between nucleus+outer shell so decreases electrostatic attraction between electron+nucleus protons;
increased shielding effect - more inner electrons shield outer electron from electrostatic force
* therefore less electrostatic force = outer electron is harder to gain = reactivity decreases down the group
* therefore boiling points increase down the group
state properties of metals (8)
- good conductors of heat+electricity
- high density
- malleable (hammered into shape)
- ductile (drawn into wires)
- high melting+boiling points (except mercury)
- react w non-metals forming positive ions
- do not react with other metals
- form basic oxides
state properties of non-metals (8)
- poor conductors of heat+electricity (except graphite)
- low density
- brittle (when solid)
- not ductile
- low melting+boiling points
- react w metals forming negative ions
- react w other non-metals forming molecules or compounds
- form acidic oxides
