IBP Nuclear and Atomic Physics - IB Preparation Quiz

What is the relative charge of a proton

• +2/3

• -1

• 0

• +1

Answer explanation

Protons are positively charged. They have a charge of + 1.60 x 10^-19 C, which we refer to as +1 as it is the opposite (positive) charge of an electron.

How many protons and neutrons does this isotope have?

• 82 protons and 35 neutrons

• 82 neutrons and 35 protons

• 47 protons and 35 neutrons

• 47 neutrons and 35 protons

Answer explanation

Bromine (Br) has 35 protons (the atomic number) and it has 82-35 neutrons = 47.

What is the name of the particle that protons and neutrons are made up of?

• electrons

• baryons

• quarks

• hadrons

Answer explanation

Protons (udu) and neutrons (udd) are baryons (a sub-classification of hadrons) - they are made up of quarks.

Name a sub-atomic particle that is found inside the nucleus of an atom. _

Answer explanation

Protons, neutrons and electrons are sub-atomic particles found inside the atom - but the electrons are not in the nucleus (so this isn't a valid answer). Quarks are also found in the atom as they combine to make protons and neutrons.

How many electrons does this Uranium nucleus have?

• 0

• 91

• 92

• 93

Answer explanation

There are no electrons in the nucleus of an atom, so the answer is zero. The atom has 91 electrons (92-1), but the nucleus has none.

What is the sub-structure of a neutron?

• two down quarks and an up quark

• two down quarks and an electron

• two up quarks and an electron

• two up quarks and a down quark

Answer explanation

Neutrons are made up of one up quark and two down quarks (udd) - as up quarks have a charge of +2/3 and a down quark have a charge of -1/3.

_ are found in discrete energy levels inside the atom.

Answer explanation

Electrons 'orbit' the nucleus of an atom in discrete energy levels.

Name a sub-atomic particle that is found inside an atom. _

Answer explanation

Protons, neutrons and electrons are sub-atomic particles found inside the atom. Quarks are also found in the atom as they combine to make protons and neutrons.

How many electrons does this ion have?

• 5

• 7

• 9

• 12

Answer explanation

The nucleus has 9 electrons, as the atom usually has the same number of protons and electrons, but as the atom has a charge overall of -2, then it must have gained two additional electrons and 7 + 2 = 9.

Isotopes are different from the 'normal' atom of that element because...

• Same mass but different size

• same nucleus but a different number of electrons

• same number of protons but a different mass

• same number of neutrons but a different mass

Answer explanation

Isotopes have the same number of protons but a different number of neutrons as the atom in the periodic table.