C4 The Periodic Table Flashcards
How are elements ordered on the periodic table
Atomic number
Problems with Mendeleev’s Periodic table
- The table was incomplete with no explanation for why some elements had to be swapped to fit in appropriate groups
- No clear distinction between metals and non-metals
- Grouped by chemical properties not number of electrons on outer shell
Describe the pattern of reactivity in group 1 (alkali) metals and explain why
Reactivity increases as you move down the group
This is because:
- As atoms size increases in group 1 the outermost electrons are further from the nucleus
- This means electrostatic attraction between the outermost electrons and the nucleus is weaker the further down the group you go
- This means that the electrons are more easily lost as weak electrostatic forces allow the electron to be transferred more easily
Describe the pattern of reactivity in group 7 (Halogens) and explain why
Reactivity decreases as you move down the group
This is because:
- As atoms size increases in group 7 the outermost electrons are further from the nucleus
- This means electrostatic attraction between the outermost electrons and the nucleus is weaker the further down the group you go
- This means that the electrons are less easily gained as weak electrostatic forces prevent the outer shell to be filled as easily
Explain why Lithium chloride would react with potassium to form potassium chloride and lithium
Potassium would displace sodium as it is more reactive than sodium
What would happen to boiling point of group 1 metals as you move down the group?
Boiling point is lower the further down group 1 because their reactivity is higher
Properties of noble gasses (group 0)
- Not very reactive (inert) as they have a full outer shell
- Boiling point increases down the group
Who is said to be the founder of the modern periodic table
Dmitri Mandeleev
