Chemistry Flashcards
what charge do electrons have?
Negative
Why did Mendeleev leave gaps in his periodic table
For elements that had not yet been discovered
Why is group 0 highly unreactive
They have a stable arrangement of electrons (full outer shell)
Sodium + water —>
Sodium hydroxide + hydrogen
Sodium + chloride —>
Sodium chloride
Sodium + oxygen
Sodium oxide
State the trend in boiling point down group 7
increases down the group
Potassium bromide + Chlorine —>
Potassium chloride + bromine
What type of reaction is this? Potassium bromide + chloride —> Potassium + bromine
Displacement reaction
How do you calculate the number of neutrons in an atom?
Mass number minus atomic number
what is an ion?
an atom which has lost or gained electrons
how many electrons can go in the first shell?
2
how many electrons can go in the second and third shell?
8
what is the definition of a displacement reaction?
A more reactive element will displace a less reactive element from a compound
are the halogens metals or non-metals?
non-metal
what colour flame is produced when potassium reacts with water?
lilac
group 7 are diatomic, what does this mean?
They exist in molecules made up of pairs of atoms e.g Br2
State the colour and state of chlorine at room temperature
green gas