which of the following are isoelectronic species:
Na+,K+,Mg+2,Ca+2,S2-,Ar
Find the pair with the equal number of valence shell electrons.
http://www.chem.ucla.edu/harding/IGOC/I/isoelectronic.html
To determine which species are isoelectronic, we need to compare the number of electrons in each species. Isoelectronic species have the same number of electrons.
Let's analyze each species:
1. Na+: Sodium ion (Na+) has lost one electron, so it has 10 electrons. To determine if other species are isoelectronic with Na+, we need to compare the number of electrons.
2. K+: Potassium ion (K+) has also lost one electron, so it has 18 electrons.
3. Mg+2: Magnesium ion (Mg+2) has lost two electrons, so it has 10 electrons.
4. Ca+2: Calcium ion (Ca+2) has also lost two electrons, so it has 18 electrons.
5. S2-: Sulfide ion (S2-) has gained two electrons, so it has 18 electrons.
6. Ar: Argon (Ar) is a neutral atom, so it has 18 electrons.
Comparing the electron counts from above, we see that Na+ and Mg+2 both have 10 electrons, so they are isoelectronic. Similarly, K+ and Ca+2 both have 18 electrons, making them isoelectronic as well. S2- and Ar also have 18 electrons, so they are isoelectronic.
Therefore, the isoelectronic species are: Na+ & Mg+2, K+ & Ca+2, S2- & Ar.