Atomic Structure

Which of the following describe the subatomic particles correctly?

• Electron has -1 charge and proton has a +1 charge.

• Neutron has a +1 charge and electron has a mass of 1/1840.

• Proton has a +1 charge and neutron has a mass of 1/1840.

• Electron has a +1 charge and electron has a mass of 1.

Answer explanation

You need to remember the charges and relative mass of the subatomic particles:

proton:

rel mass: 1, charge: +1, in nucleus of atom

electron:

rel mass: 1/1840, charge: -1, in electron shells

neutron:

rel mass: 1, charge: 0 (neutral, no charge), in nucleus of atom

Atoms of the same element with a different number of neutrons are called _______.

• Ion

• Gluons

• Isotope

• Quarks

Answer explanation

Remember the definition of isotope:

Isotopes are atoms of the same element with same number of protons, but different number of neutrons.

What is proton (atomic) number?

• Number of protons in the nucleus of an atom

• Number of neutrons in an atom

• Mass of an atom

• Charge on an atom

Answer explanation

Proton (atomic) number is the number of protons in the nucleus of an atom.

The no. of protons is equal to no. of electrons in an atom --> protons have charge of +1 and electrons have charge of -1, thus, this makes an atom electrically neutral.

Which subatomic particles are found in the nucleus of an atom?

• Protons and Electrons
• Protons and Neutrons
• Neutrons and Electrons
• Protons, Neutrons and Electrons

Answer explanation

Electrons are in the electron shells.

Protons and neutrons are in the nucleus of an atom

Tags

NGSS.MS-PS1-1

How many protons does an aluminium atom have? (Use the image to help you)

• 27
• 14
• 40
• 13

Answer explanation

This is a nuclide notation --> proton no the smaller no. is at the bottom.

Tags

NGSS.MS-PS1-1

The total number of protons and neutrons in an atom is called the...

• Atomic number

• Proton number

• Mass number

• Nucleus number

• Nucleon number

Answer explanation

Protons and neutrons are found in the nucleus, and each have a relative mass of 1.

Thus, they make up the nucleon(mass) number in the Periodic Table.

How many neutrons does a sodium atom have? (Use the image to help you)

• 23

• 11

• 12

• 34

Answer explanation

This is nuclide notation, where the nucleon(mass) no (bigger no) is at the top.

Nucleon no is the p & n

p + n = 23

Atoms of the same element must always have the same number of _________

• electrons
• neutrons
• isotopes
• protons

For an atom to be electrically neutral, it must contain the same number of _____

• protons and neutrons
• neutrons and electrons
• protons and electrons
• nucleons and electrons

Answer explanation

Atoms have same no. of protons (rel charge +1) and electrons (rel charge -1). Thus they are electrically neutral.

Tags

NGSS.MS-PS1-1

Which of the following electronic configurations will form a negative ion with charge of 2-?

• 2,8,2

• 2,8

• 2,6

• 2,1

Answer explanation

Non-metal atom gains electron to form negative ion!

EC 2,6 --> gains 2 electrons --> Ion of 2- charge

Electron rel charge : -1.