topic 1 - atoms
- Created by: Stephcooper_xox
- Created on: 18-03-19 15:25
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Topic 1 - Atomic structure and the periodic table
Atoms
Atoms contain protons, neutrons and electrons.
the nucleus-
- in the middle of the atom
- contains protons and neutrons
- positive charge (becuase of protons)
- whole mass of atom is in the nucleus
the electrons-
- move around nucleus is shells (2,8,8...)
- negatively charged
- virtually no mass
- particle relative mass relative charge
proton 1 +1
neurton 1 0
eletron very small -1
number of protons equals the number of electrons-
- atoms are neutral (no overall charge unlike ions)
- this is because there is the same number of protons as there is electrons
- in an ion the protons and electrons dont equal the same (has an overall charge)
atomic number & mass number-
- atomic number = amount of protons
- mass number = total number of rotons and neutrons
eg
23 - mass number
Na - element
11 - atomic number
elements-
- elements consist iof atoms with the same atomic munber
- its number pof protons decides which type of atom its is
- eg an atom with only one proton in its nucleus is hydrogen.
isotopes-
- differnt forms of an element, same numver of protons, differnt number of neutrons.
- eg carbon 12 has 6 protons, 6 electrons and 12 neutrons.
carbon 13 has 6 protons, 6 electrons BUT 13 neurtons.
- relative atomic mass = (sum of isotope abundance X isotope mass number)
- sum of abundances of all isotopes
compounds-
- atoms join together to form compounds when they react with one another, held together by chemical bonds.
- making bonds involves giving away, taking or sharing electrons.
- a compound formed from a metal and non metal is done through ionic bonding. this is where the metal atoms lose electrons becoming positively charged and the non metals gain electrons becoming negativeky charged.
- opostite charges mean that they are strongly attracted to eachother.
- a compound formed from non metals conatin monocules - this is throigh covalent bonding where each atom shares an electron with another atom.
- in order to form compounds each atom must be left with a full outer shell of electrons.
- the properties of a compound are usually totally different to the origional element.
formulas & equations-
- elements are represented by symbols - compounds are represented by formulas
- eg CO2 - 1 carbon atom, 2 oxygen atoms > carbon dioxide
- chemical changes are shown usuing chemical equations.
- eg methane + oxygen > carbon dioxide + water
- ( reactants ) …
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