ScienceFreePrintable

Atomic Structure Knowledge Check

A free science worksheet ready for your classroom. Open in Kuraplan to grab the print-ready PDF, customize it for your students, or generate a fresh version in seconds.

Download now

Name:Date:

Atomic Structure Knowledge Check

Use the atom facts and diagrams on this worksheet to investigate each claim. Choose or write the best answer, and explain your reasoning where asked.

Build and read atoms

An atom has a tiny central nucleus containing protons and neutrons. Electrons occupy regions called shells around the nucleus. For the first 20 elements, a simple shell model fills the first shell with up to 2 electrons, the second with up to 8, and the third with up to 8. Atomic number 8 is oxygen.

1.In a neutral atom, which statement describes the relationship between protons and electrons?

There are the same number of protons and electrons.
There are the same number of protons and neutrons.
There are always more electrons than protons.

2.A neutral atom has 8 protons. How many electrons does it have, and which element is it?

3.An atom contains 11 protons, 12 neutrons and 10 electrons. Is it neutral, positive or negative? Explain using the particle charges.

4.A fluorine atom has 9 electrons. Use the shell diagram to show how they are arranged. Write the number of electrons in each shell.

Atomic number, mass number and isotopes

Atomic number = number of protons. Mass number = number of protons + number of neutrons. Isotopes are atoms of the same element with different numbers of neutrons, so they have the same atomic number but different mass numbers. Atomic number 17 is chlorine.

5.A carbon-12 atom has atomic number 6. Calculate how many neutrons it contains. Show the calculation.

6.Two atoms are both carbon. Atom A has 6 protons and 6 neutrons; atom B has 6 protons and 8 neutrons. What is the key difference between these atoms?

They are isotopes because they have different numbers of neutrons.
They are different elements because they have different numbers of neutrons.
They must have different numbers of protons.

7.A student says, “Electrons travel around the nucleus in fixed circular tracks, just like planets around the Sun.” Is this a fully accurate modern description? Give one reason.

TrueFalse

8.Which statement about an atom's nucleus is correct?

It contains protons and neutrons and most of the atom's mass.
It contains electrons and takes up most of the atom's volume.
It contains only neutrons and has no mass.

9.An atom has 17 protons and 18 neutrons. Find its atomic number and mass number. Name the element using its proton number.

10.The first electron shell can hold a maximum of 2 electrons. Is this statement true or false? What is the maximum number in the second shell in the simple model used here?

11.Exit challenge: A neutral atom has mass number 23 and atomic number 11. State the number of protons, neutrons and electrons, then explain how you worked out the neutron number.