Hey! Sign in to get help with your study questionsNew here? Join for free to post

GCSE Redox Reaction (involving rusting of iron)

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016
    • Thread Starter

    SO I am using the CGP OCR Gcse Chemistry revision guide and is says:

    That the rusting of iron is a redox reaction: iron+oxygen+water > hydrated iron(iii) oxide
    The explanation in the book is:
    1) Iron loses electrons when it reacts with oxygen. Each Fe atom loses three electrons to become Fe3+
    2) Oxygen gains electrons when it reacts with iron. Each O atom gains two electrons to become O2-

    So, could you please explain the following to me:
    1) Why each Iron Fe atom lose three electrons when it reacts with oxygen?
    2) If three electrons are lost from the Iron to become Fe3+, why does each Oxygen O atom only gain two electrons to become O2-? Surely it should gain 3 electrons since 3 are lost from the iron?

    Thank you so much

    It's because oxygen has 6 electrons in its outer shell so it needs to gain electrons which it takes from the Iron...I'm not too sure about the second part.
Write a reply…


Submit reply


Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: April 30, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Do you like sleeping in a cold room?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.