Calcium atom in 3D
Bones, limestone and signalling. Calcium compounds occur in bones, teeth and limestone. Calcium ions also help coordinate cellular signals. Explore the 3D model, inspect its parts and learn with guided explanations. Free on Atlas.
What you can learn
Bones, limestone and signalling. Calcium compounds occur in bones, teeth and limestone. Calcium ions also help coordinate cellular signals.
Identify calcium from its proton count.
Count the neutrons in Calcium-40.
Inspect the occupied electron shells.
Compare the valence shell with a neighbouring element.
Explain what changes when an electron is lost.
Bones contain calcium compounds, not pieces of calcium metal. Neutral calcium has the shell count 2, 8, 8, 2.
Try an investigation
Identify calcium from its proton count.
Check your understanding
What identifies an atom as calcium?
20 protons. Atomic number is proton count. Every calcium nucleus has 20 protons.
How many neutrons are in Calcium-40?
20. Neutrons = mass number − atomic number = 40 − 20 = 20. Mass number is not the average atomic weight of natural samples.
How many electrons are in a neutral calcium atom?
20. A neutral atom balances 20 positive protons with 20 negative electrons.
Which shell count describes neutral calcium in its ground state?
2, 8, 8, 2. [Ar] 4s² gives 2, 8, 8, 2 electrons across its occupied shells. Circular paths are only diagram guides.
If this atom loses one electron, what happens to its net charge?
It becomes +1. Losing one negative electron leaves one more proton than electrons. Its 20 protons still identify it as calcium.
What can this 3D shell model tell you reliably?
The particle counts for the selected neutral isotope. The counts represent a defined isotope and neutral atom. Particle sizes, spacing and circles are simplified teaching symbols.
Sources and model scope
An educational representation. The explorer identifies its data sources, scale choices and simplifications.