Chapter 2- The Periodic Table Flashcards
Who is the most credited person for the periodic table?
Dmitri Mendelev
Did he arrange ALL elements?
No he left gaps for others to be discvoered.
How is the periodic table arranged?
In order of increasing atomic mass
How many periods are in the periodic table?
7
What will the period correspond to?
How many shells that element has
Vertical colums are….
Groups
What do the groups correspond to?
The number of electrons in the last shell.
How many blocks are in the periodic table?
4
What is block s
groups 1&2
What is block p
groups 13-18
What is block d
groups 3-12
What is block f
“inner transition elements”
Summarise trends in the periodic table for atomic size
Increase down a group and decrease across as period
Why does the atomic size increase down a group?
Electrons are added to higher energy levels, they move further away from the nucleus
Why does the atomic radius decrease across a period?
Each element has an extra proton and electron than the previous element. therefore the attraction force increase and pulls the electrons closer towards the nucleus.
Define Ionisation Energy
The energy required to remove an electron from a single atom
Summarise trends in the periodic table for ionisation energy
Decreases down a group and increases across a period
Why does the ionisation energy decrease down a group?
Atomic size is increasing and electrons are moving furhtue away from the nucleus therefore more easily removed
Why does the ionisation energy increase across a period?
Electrons have a higher attraction for the nucleus and have a stronger connection, therefore harder to remove.
Define electronegativity
Degree in which an atom can attract an electron to itself.
What are the lease electronegative?
Francium and Caesium (0.7)
What are the most electronegative?
Fluorine (4.0)
Summarise trends in the periodic table for electronegativity
- Across a period from left to right it increases
- Down a group the electronegativity decrease
What is metalliac characteristics in regards to the periodic table?
-Are determined by how easy it is to loose one of its electrons
Summarise trends in the periodic table for metalliac character
- Decrease across a period
- Increase down a group
Define Oxidising Strength
How readily an element gains electrons.
Define Reducing Strength
How readily an element looses electrons
Summarise trends for reactivity
Metals Across a period decreases -Down a group increases Non-Metals Across a period increases Down a group decreases
Are cations or anoins smaller?
Cations
