Atomic structure & the periodic table

Question 1

What is the structure of an atom?

Answer 1

A nucleus containing protons and neutrons, surrounded by electrons in shells.

The protons are positively charged, neutrons are neutral, and electrons are negatively charged.

Question 2

What is an isotope?

Answer 2

Atoms of the same element with the same number of protons but different numbers of neutrons.

Isotopes can have different physical properties, such as mass and stability.

Question 3

What is the periodic table arranged by?

Answer 3

Increasing atomic number.

The atomic number is the number of protons in the nucleus of an atom.

Question 4

Why do elements in the same group have similar chemical properties?

Answer 4

They have the same number of electrons in their outer shell.

This similarity in electron configuration leads to similar reactivity and bonding characteristics.

Question 5

What are the trends in Group 1 (alkali metals)?

Answer 5

Reactivity increases, melting and boiling points decrease down the group.

This is due to the increasing atomic size and the decreasing attraction between the outer electrons and the nucleus.

Question 6

What are the trends in Group 7 (halogens)?

Answer 6

Reactivity decreases, melting and boiling points increase down the group.

This is attributed to the increasing atomic size and the difficulty in gaining an additional electron.