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Atomic Structure Worksheet

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Atomic Structure Worksheet

A lab has received three unknown samples. Use atomic number, mass number and ion charge to work out what each atom contains. Assume all atoms and ions are made from protons, neutrons and electrons. Show your working where useful.

Particle reference

Use this reference for the questions. Relative masses are approximate.

Proton | Charge +1 | Relative mass 1 | In the nucleus

Neutron | Charge 0 | Relative mass 1 | In the nucleus

Electron | Charge −1 | Relative mass about 1/1836 | In the electron cloud around the nucleus

1.A neutral atom has atomic number 11. What does this tell you about its number of protons, and how many electrons does it have?

2.An atom is written as ²³₁₁Na. Identify its atomic number and mass number, then calculate its number of neutrons.

3.Which statement best describes where most of an atom’s mass is found?

In the electron cloud, because electrons have the greatest mass
In the nucleus, because it contains protons and neutrons
Evenly throughout the atom
Only in the electrons

4.Complete the particle count for a neutral carbon-12 atom: protons = , neutrons = , electrons = . Carbon’s atomic number is 6.

5.A magnesium atom loses two electrons. State the ion’s charge and explain how the particle counts produce that charge. Magnesium has atomic number 12.

6.True or false: two atoms of the same element can have different numbers of neutrons. Explain using the term isotope.

7.Chlorine has atomic number 17. Compare chlorine-35 and chlorine-37: calculate the number of neutrons in each isotope and state what stays the same.

8.An unknown neutral atom has 8 protons and 10 neutrons. Identify its element using atomic number, calculate its mass number, and give its electron count.

9.A student says, “An atom becomes negative when it loses electrons.” Is this correct? Correct the statement and explain why.

10.An ion contains 13 protons, 14 neutrons and 10 electrons. Write its element symbol and charge, then give its mass number.

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Atomic Structure Worksheet

Atomic Structure Worksheet

Particle reference

2 printable pages

About This Worksheet

Free in Kuraplan

Print-Ready

AI-Generated

For Teachers & Parents

Need a custom version of this worksheet?

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