Periodic table and atoms
Element = made of only one kind of atom
Elements are arranged in order of ascending proton number in the periodic table
Group = vertical column of elements, corresponds to the number of electrons in the shell of an atom
Period = horizontal row elements, corresponds to the number of shells in an atom
Nucleus = made up of protons and neutrons
Nucleus surrounded by electrons arranged in shells
Atoms has no overall charge
Spectroscopy and Electron configuration
Line spectrum = light emitted from flame of an element when heated
Lithium = red flame
Sodium = yellow flame
Potassium = lilac flame
Electron configuration = how the electrons are arranged around nucleus
First shell = maximum of 2 electrons
Shells after this = maximum of 8 electrons
Total mass of products = total mass of reactants
No atoms are lost or made in a chemical reaction
There are 4 steps to write a balanced equation...
- write word equation
- substitute in formulae
- balanced the equation by adding numbers in front of reactants/products
- write balanced symbol equation
- group 1
- 1 electron in outer shell
The reactivity of alkali metals increases down the group
Alkali metals are more reactive down the group as the outer shell gets further from the nucleus and electrons are more easily lost.
Alkali metal + water = metal hydroxide + hydrogen
Halogens are in group 7 and have 7 electrons in outer shell
The reactivity of halogens decreases down the group
At room temperature and room pressure....
- chlorine is a green gas
- bromine is an orange liquid
- iodine is a dark purple solid
Halogens are less reactive down the group as the outer shell gets further from the nucleus and electrons are less easily gained.
A more reactive halgen will displace a less reactive halogens from an aqueous solution of its salt.
Ions = atoms that have gained or lost electrons so have an overall charge
Ionic bonding = transfer of electrons between metal atoms and non metals atoms
Atom loses electrons = positively charged ion
Atom gains electrons = negatively charged ion
Ionic compound = compounds of group 1 and group 7 elements. Form crystals as ions are arranged in regular lattice.
Ionic compounds = neutral substances = equal amounts of positive and negative charge.