MediumChemistryHigh School (9–10)GeneralStructure of the Atom › Electronic Configuration and ValencyStructure of the Atom › Isotopes and IsobarsNumerical
Lithium-7 has an atomic number of 3. The lithium ion, Li⁺, has a charge of +1.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Lithium-7 has an atomic number of . The lithium ion, , has a charge of . How many protons, neutrons and electrons are there in this ion?
Need a reminder? The key ideaShow
The atomic number is the number of protons, and it decides the element. The mass number is protons plus neutrons, so neutrons . A neutral atom has electrons. An ion has the same nucleus; only the electrons change, by the charge.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Protons. , so protons.
Step 2. Neutrons. .
Step 3. Electrons. The atom has ; the ion has lost : .
Answer: protons, neutrons and electrons, the arrangement of helium.
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