Electron Configuration in Ionic Bonding Ionic Bonds Bonding in Metals

Transcription

1 Electron Configuration in Ionic Bonding Ionic Bonds Bonding in Metals Valence Electrons Electrons in the highest occupied energy level of an element s atoms Examples Mg: 1s 2 2s 2 2p 6 3s 2 2 valence e - in level 3 Br: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5 7 valence e - in level 4 Identification of group number gives valence electrons for the representative elements Group 1A elements (i.e., hydrogen, lithium, etc.) have 1 valence electron Group 6A elements (i.e., oxygen, sulfur, etc.) have 6 valence electrons Usually the only electrons used in chemical bonds Only electrons shown in the electron dot structures

2 Electron Dot Structures Oxygen Nitrogen Sodium Calcium (6 valence e - ) (5 valence e - ) (1 valence e) (2 valence e - ) Electron Configurations for Ions Ions strive to become like noble gases Octet rule Atoms tend to achieve the electron configuration of a noble gas Ions strive to have 8 valence electrons Metals will lose electrons to go back to a noble gas configuration in the greatest energy level of their electron configurations Nonmetals will gain electrons to go to a noble gas configuration in the greatest energy level of their electron configurations Transition metals will go to a pseudo-noble gas configuration in their electron configurations

3 Electron Configurations for Cations 1s 2 2s 2 2p 6 3s 1 1s 2 2s 2 2p 6 + e - Electron Configurations for Cations 1s 2 2s 2 2p 6 3s 2 1s 2 2s 2 2p 6 + 2e -

4 Electron Configurations for Cations 1s 2 2s 2 2p 6 3s 2 3p 1 1s 2 2s 2 2p 6 + 3e - Electron Configurations for Cations (Transition Metals) Ideally, transition metals would have to lose their d orbital electrons to achieve a noble gas configuration. Example: Cobalt (1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 7 ) would have to lose nine electrons to get back to a noble gas configuration. Transition metals can have pseudo-noble gas electron configurations by typically losing the s orbital electrons. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 7 1s 2 2s 2 2p 6 3s 2 3p 6 3d 7 15 electrons in the outer energy level Still a pseudo-noble gas configuration because of the s and p orbitals being filled

5 Electron Configurations for Anions 1s 2 2s 2 2p 3 + 3e - 1s 2 2s 2 2p 6 Electron Configurations for Anions 1s 2 2s 2 2p 4 + 2e - 1s 2 2s 2 2p 6

6 Electron Configurations for Anions 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5 + 1e - 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 -- Ionic Bonds -- Ionic Bonds Forces of attraction that bind oppositely charged ions Examples Sodium chloride Na + attracted to a Cl - Aluminum bromide Al 3+ attracted to 3 Br - Electromagnetic attraction Transfer (NOT sharing) of electron(s) from one neutral atom to another neutral atom to create ions Each ion will have an octet in the outer shell Exceptions: transition metals

7 -- Ionic Bonds -- Formation of Ionic Bonds 1s 2 2s 2 2p 6 3s 1 1s 2 2s 2 2p 6 3s 2 3p 5 1s 2 2s 2 2p 6 1s 2 2s 2 2p 6 3s 2 3p 6 Transfer of the 3s 1 electron of the Na to the p orbital of the Cl Both ions now have octets -- Ionic Bonds -- Formation of Ionic Bonds 1s 2 2s 2 2p 6 3s 2 1s 2 2s 2 2p 4 1s 2 2s 2 2p 6 1s 2 2s 2 2p 6 Transfer of the 3s 2 electrons of the Mg to the p orbital of the O Both ions now have octets