7.1 The Periodic Table

Question 1

Who created the original periodic table? What did it look like?

Answer 1

Mendeleev

Arranged in order of atomic mass
Lined up elements in groups of similar properties
Left gaps and swapped elements around

Question 2

What happened involving the periodic table in the 1990’s?

Answer 2

Protons were discovered and the real reason for the order in Mendeleev’s table was revealed.

Question 3

How are the elements organised in the periodic table?

Answer 3

Arranged in order of increasing atomic number

Arranged in groups with same number of outer shell electrons and similar properties

Arranged in periods with repeating trends in physical and chemical properties

Question 4

Define periodicity

Answer 4

Repeating trends in properties of the elements

Question 5

What is the periodic trend in electron configuration?

Answer 5

Across period 2, the 2s sub shell fills with two electrons, followed by the 2p sub shell with six electrons

Same for period 3

In period 4, although there is 3d, n= 4 is the highest shell number so only the 4s and 4d sub shells are occupied

Question 6

What is the trend down a group ?

Answer 6

Same number of electrons in each sub shell.

This similarity gives elements in the same group their similar chemistry.