1. Ions are formed by loss or gain of electrons.
QUESTION:
A nitrogen atom becomes a nitride ion (N3-) by… A. gaining 3 electrons, B. losing 3 electrons C. gaining 3 protons, D. losing 3 protons
Ions are formed by loss or gain of electrons.
A negatively-charged ion is formed by gaining electrons. [Each electron has a –1 charge]
A charge of -3 means a gain of 3 electrons.
Name of negative ion formed when an atom gains electron(s) ends in “ide”
Standard way of indicating negative charges:
-, 2-, 3-, etc.
In older textbooks, you may see –2, - -, or = instead of 2-
SCRIPT:
A nitrogen atom becomes a nitride ion (N3-) by… A. gaining 3 electrons, B. losing 3 electrons C. gaining 3 protons, D. losing 3 protons PAUSE
CLICK Ions are formed by loss or gain of electrons, not protons.
So, immediately, we can rule out choices C and D.
CROSS OUT C and D
CLICK
A negatively-charged ion is formed by losing electrons. Remember that each electron has a –1 charge.
The number you see written on the upper right hand corner
HIGHLIGHT 3-
Is the charge of the ion.
Therefore, the ion given here ---- nitride ion --- is a negatively charged ion.
CLICK Since the charge of nitride ion is –3, it is formed when a nitrogen atom gains three electrons.
The correct answer is A.
CLICK Note.. The name of a negative ion forme dwhen an atom gains electrons ends in “ide”
HIGHLIGHT “ide”
Also,… the standard way of indicating negative charges is to write a minus sign if the charge is -1,
HIGHLIGHT 2- if the charge is -2
HIGHLIGHT 3-, if the charge is -3,
And so on….
With older textbooks, however, you may see a -2 charge written
with the minus sign in front of the number
HIGHLIGHT -2
Or with two minus signs
HIGHLIGHT -- and =.
CLICK PAUSE END RECORDING

2. Video ID: © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08