Periodicity Flashcards
What is the periodic table arranged into?
Rows and columns
What do the rows represent?
Periods
What do the columns represent?
Groups
What do all elements in a period have in common?
They have the same number of electron shells
What do all elements in a group have in common?
They have the number of electrons in the outer shell
Therefore, they have similar properties
Which blocks is the periodic split into?
s,p,d,f
What happens to the atomic radius across a period?
The atomic radius decreases
Why does the atomic radius decrease across a period?
The number of protons increases as well as the positive charge of the nucleus
The electrons are pulled closer
What factors affect the melting point?
Bond strength
Structure
What is the trend in the melting and boiling points of sodium, magnesium and aluminium?
Their melting and boiling points increase
Why do the melting and boiling points increase for sodium, magnesium and aluminium?
The metallic bonds become stronger due to the increasing positive charge, increasing number of delocalised electrons and a decreasing radius
Why doe silicon have a high melting point?
It is macromolecular
there are strong covalent bonds
Why do phosphorus,sulfur and chlorine have low melting points?
They are molecular substances
They only have van der Waals forces which can be easily overcome
Why does sulfur have a melting point than phosphorus and chlorine?
It is the biggest molecule
S8
Why does argon have a very low melting point?
It exists as individual atoms
There are very weak van der Waals force
