How are the elements arranged in the Periodic Table?

In order of increasing proton number

What does the group number of a main-group element tell you?

The number of electrons in the outer shell

Potassium's outer electron is further from the nucleus and lost more easily

They have full outer electron shells

In a central block between Groups II and III

Harder, denser and with higher melting points

They often act as catalysts and form coloured compounds

14questions. Pick an answer and you'll see why right away.

How are the elements arranged in the Periodic Table?
What does the group number of a main-group element tell you?
What does the period number tell you about an atom?
An element has the electron arrangement 2, 8, 1. Which group and period is it in?
What are the Group I metals called?
How does the reactivity of the Group I metals change down the group?
Why does potassium react more vigorously with water than sodium?
What are the Group VII non-metals called?
How does the reactivity of the Group VII non-metals change down the group?
Why are the Group 0 noble gases very unreactive?
Where are the transition metals found in the Periodic Table?
Which of these is a property of the transition metals compared with the Group I metals?
Which property is typical of the transition metals?
On which side of the Periodic Table are most non-metals found?