Ch_08b - Valence shell: the outmost occupied principal...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
22 Valence shell : the outmost occupied principal shell. Valence electrons : e- in the outmost occupied principal shell of an atom. Core electrons : e- in inner shells; their principal quantum numbers are less than valence shell n . Calcium Ca 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2 or [Ar] 4 s 2 4 s electrons (two) are valence electrons; Those in [Ar] are core electrons. Bromine Br [Ar]3 d 10 4 s 2 4 p 5 Seven valence electrons in 4 s 2 4 p 5 . Core electrons are in [Ar]3 d 10 . 23 Electron Configurations and The Periodic Table • For main-group (A-group) elements, the number of valence e- = group number . • Elements with similar electron configurations fall in the same group • The period number = principle quantum number n of the valence shell
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
24 Electron Configuration of Anions A nonmetal atom gains electrons to form an anion attains the electron configuration of a noble gas atom. Cl ([Ne]4 s 2 4 p 5 ) + e - Cl ([Ne]4 s 2 4 p 6 or [Ar]) S ([Ne]3 s 2 3 p 4 ) + 2 e - S 2 ([Ne]3 s 2 3 p 6 or [Ar]) O ([He]2 s 2 2 p 4 ) + 2 e - O 2 ([He]2 s 2 2 p 6 or [Ne]) 25 Electron Configuration of Cations s -block metals (Group 1A & 2A) lose valence electrons to attain electron configuration of a noble gas atom. Na ([Ne] 3 s 1 ) Na + ([Ne]) + e Mg ([Ne] 3 s 2 ) Mg 2+ ([Ne]) + 2 e p -block (Group 3A through 8A) metals of fourth period and beyond Ga ([Ar]3 d 10 4 s 2 4 p 1 ) Ga 3+ ([Ar]3 d 10 ) + 3 e • Transition metals Fe ([Ar]3 d 6 4 s 2 ) Fe 2+ ([Ar]3 d 6 ) + 2 e Fe ([Ar]3 d 6 4 s 2 ) Fe 3+ ([Ar]3 d 5 ) + 3 e Note: In forming cations, 4s electrons are removed first.
Background image of page 2
26 Magnetic Properties: Paired and Unpaired Electrons Diamagnetism • Associated with paired electrons • The substance with all electrons paired is weakly repelled by a magnetic field. Paramagnetism
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 11

Ch_08b - Valence shell: the outmost occupied principal...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online