Positive Ions Flashcards

All 5 cards in this deck

What is a positive ion?

An atom that has lost one or more outer electrons, so it has more protons than electrons.

Which electrons does an atom lose when it forms a positive ion?

Outer electrons — they are furthest from the nucleus and least strongly held.

What are the steps to work out the charge on a positive ion?
e.g. a lithium atom (3 protons) loses 1 outer electron

1. Count the electrons lost: 1
2. Compare protons with remaining electrons: 3 protons, 2 electrons
3. Charge is $+1$ for each electron lost: charge $=+1$

True or false? An atom becomes a positive ion by gaining protons.

False. It loses outer electrons; the nucleus is unchanged.

Does forming a positive ion change an atom's mass number?

No. Only electrons are lost, and the nucleus (protons and neutrons) is unchanged.