7.1 - The Periodic Table

Question 1

What was the prior periodic table like?

Answer 1

• Only 60 known elements
• Arranged in order of atomic mass
• No knowledge of subatomic particles
• Elements were swapped in places where their properties didn’t match their groups
• Gaps were left in the periodic table for predicted and undiscovered elements

Question 2

How are elements arranged in the modern day periodic table?

Answer 2

• Elements from L to R, arranged in order of increasing atomic number (each successive member with 1 extra proton)
• Groups (18) are vertical columns - each element in a group has the same number of electrons in its outer shell
• Periods (7) are horizontal rows - each element in a period has the same number of the higher energy electron shell

Question 3

Define periodicity.

Answer 3

Repeating trend in properties across elements in the period.

Question 4

Where are the s, p and d blocks situated in the periodic table?

Answer 4

s block - groups 1 & 2
d block - groups 3-12
p block - groups 13-18
f block - bottom