Ions are formed by loss or gain of electrons.

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Presentation transcript:

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

Video ID: 1-14-3 © 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