1c Atomic Structure

Question 1

What are atoms made of?

Answer 1

Every atom consists of a nucleus and electrons that move around the nucleus. The nucleus itself is a cluster of two sorts of particles (neutrons and protons). In the nucleus the neutrons and the protons form a cluster. This is the nuclear part of an atom. The electrons circle around the nucleus, they are very light in weight compared to the nucleus. In an atom the number of protons in a nucleus is always equal to the number of electrons moving around it.

Question 2

How many electrons do each of the shells contain?

Answer 2

• The first shell can hold up to 2 electrons
• The second shell can hold up to 8 electrons
• The third shell can hold up to 8 electrons
  Atomic number = no of protons
  Mass number = Protons + neutrons
  no of electrons= no of protons

Question 3

Why does an atom have no charge?

Answer 3

An atom has no charge because neutrons have no charge but the protons and electrons balance each other out as there are the same amount of them in the atom. If you take a proton away, the atom becomes positively charged. If you take an electron away then the atom becomes negatively charged.

Question 4

What is an isotope?

Answer 4

Isotopes are atoms of the same element with the same number of protons but different number of neutrons in the nucleus. They have the same atomic number but different mass numbers. Their physical properties are different.

Chlorine has two naturally occurring isotopes: chlorine - 35 and chlorine - 37. It has an average atomic weight of 35.5