Structure of the atom

Question 1

location of protons, neutrons and electrons

Answer 1

atoms have a central nucleus containing protons and neutrons

electrons move around the nucleus of an atoms

an atom has the same number of protons and electrons, so the + and - charges balance to produce no overall charge

Question 2

the atom and the nucleus (6)

Answer 2

• all atoms have a positively charged nucleus as it contains protons with a + charge
• the nucleus contains more than 99% of the atoms overall mass
• the total number of protons in the nucleus is the same as the total number of electrons in the shells
• electrons in atoms always have a - charge and orbit the nucleus
• atoms are neutral because the + charge from protons cancels out the - charge from the electrons
• the nucleus of an atom of an element may contain a different number of neutrons

Question 3

atoms and molecules (3)

Answer 3

a molecule is two or more atoms bonded together

a molecule is 10x the diameter of an atom and 10 million times the diameter of a nucleus

gases such as oxygen and CO2 are molecules

Question 4

diameter of an atom and nucleus

Answer 4

atom: 10[-10]m
nucleus: 10[-15]m

diagrams of atoms are always incorrect in terms of scale

Question 5

A molecule has a length of 4.8x10[-9] m. A nucleus has a diameter of 1.2x10[-15]m. How many nuclei would need to be placed side by side in a line to have the same length as the molecule? [3]

Answer 5

4.8x10[-9] m / 1.2x10[-15] m = 4 x 10[6] or 4 million nuclei

Question 6

A poster shows a diagram of an atom that is not drawn to scale. The overall diameter of the atom on the poster is 60cm. Calculate the diameter of the nucleus on the poster if it was properly drawn to scale. [4]

Answer 6

the diameter of an atom is around 100,000 times greater than the diameter of a nucleus

the diameter of the nucleus on the poster will be about 60cm/100,000 or a diameter of about 6 x 10[-4] cm