The Periodic Table Flashcards
Mass of an electron
1/1836
Atomic number
The number of protons
Atomic mass
The number of protons and neutrons
Describe an isotope
Atoms of the same element with the same atomic number but different atomic mass
How is the periodic table arranged?
By increasing atomic number
What are Groups
Columns
What are Periods
Rows
Elements in the same Group have…
The same number of electrons in the outer shell
Elements in the same Period have…
The same number of electron shells
Inert
Unreactive
Which Group has inert elements and why?
Group 0/8 because the outer shell of electrons are full
Properties of Group 1 (Alkali metals) elements
Dull on oxidation. Highly reactive – reactivity increases down the Group. Low melting and boiling points.
Alkali metals when reacting with water
Fizzing, move around quickly, float on the surface. Potassium sets on fire with lilac flame.
2Li + H2O -> 2LiHO + H2
Lithium + Water -> Lithium hydroxide + hydrogen
What are Group 7 elements called?
The halogens
What are halogens?
Diatomic atoms
What are the diatomic atoms?
HOBrFINCl Hydrogen Oxygen Bromine Fluorine Iodine Nitrogen Chlorine
How does the state and colour change down the halogens Group?
Down the group the states change from gas to solid (F - gas, Cl - gas, Br - liquid, I - solid) and colour gets darker (F - pale yellow, Cl - green, Br - orange/brown, I - dark purple/black)
How does reactivity change in the halogens Group?
Reactivity decreases down the group
What is a displacement reaction?
A chemical reaction where a more reactive element replaces a less reactive element.
Displacement equation
Potassium bromide + chlorine -> Potassium chloride + bromine
2KBr + Cl2 -> 2KCl + Br2
What is produced when halogens react with hydrogen
Hydrogen halides which are poisonous gases, soluble in water, react with water to form a solution of acids e.g hydrochloric acid
What is produced when halogens react with alkali metals
Salts e.g sodium chloride
