What is an ion and how are they formed?

An ion can be an atom or a group of atoms that are charged. This means they can be positively charged or negatively charged.A positive ion is formed when the atom loses electrons. Because electrons have a negative charge think of it as the atom losing a bit of negativity- and therefore becomes positively charged. For example:The atom sodium (Na) has 11 electrons. 2 electrons in its first energy shell, 8 in its second energy shell and 1 in its outermost shell. When sodium becomes an ion, it loses the outer electron to become Na+. A negative ion is formed when the atom gains electrons. Using the same thinking as above, if an atom gains a negatively charged electron it itself will become negative. For example, the oxygen atom has 8 electrons. 2 in its first energy shell, 6 in its outermost energy shell. To become a full outer shell, oxygen gains 2 electrons. This is 2 extra negative charges. Therefore oxygen becomes O2-

Answered by Maisie D. Chemistry tutor

2225 Views

See similar Chemistry GCSE tutors

Related Chemistry GCSE answers

All answers ▸

A student titrates 25.00 cm3 of hydrochloric acid with 28.60 cm3 sodium hydroxide solution of concentration 0.200 moles per dm3. The equation for the reaction is: HCl + NaOH to NaCl + H2O. Calculate the concentration of the hydrochloric acid.


A colourless liquid is tested with silver nitrate solution and produces a white precipitate and produces a brick red flame test result. Name the compound found in the colourless liquid


How many electrons are in a chloride ion Cl- and how are they arranged in the shells? a periodic table can be used.


Describe how ethanol is produced from ethene.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences