![Valence and chemical reactivity
Noble gases: s2p6 configuration
Ne: 1s22s2p6
Electronegative – if it is almost full, the atom has
a tendency to gain enough electrons to fill the
shell
Cl: 1s22s2p63s2p5 or [Ne] 3s2p5
Cl + 1e = Cl- negative ion (anion)
Electropositive – if it is almost empty, it easily
losses the electrons in the outer shell (typically
metals)
K: 1s22s2p63s2p64s1 or [Ar] 4s
K – 1e = K+ positive ion (cation)](https://image.slidesharecdn.com/atomicsructureandbonding-160118212136/85/Atomic-sructureandbonding-4-320.jpg)
Atomic sructureandbonding
- 1. CHEMISTRY ATOMIC SRUCTURE AND BONDING Short video tutorial series
- 2. • So … what are the possible combinations of states? • Notation n L 1 K 0 s 2 L 1 p 3 M 2 d 4 N 3 f • We can describe an electron state as 1s or 3p or 5f Energy levels of the electron states • the energy of an electron is determined by its state • If there is only one electron in the atom, the energy depends on n alone • If there are more electrons, they interact (repel each other), and so different states have different energies
- 3. valence The electrons in the outer shell (largest n) are called valence electrons Very important for chemical reactions and holding matter together If the outer shell is filled, the atom is inert If not, there is a tendency for the outer shell to become filled Electronegative – if it is almost full, the atom has a tendency to gain enough electrons to fill the shell Electropositive – if it is almost empty, it easily losses the electrons in the outer shell
- 4. Valence and chemical reactivity Noble gases: s2p6 configuration Ne: 1s22s2p6 Electronegative – if it is almost full, the atom has a tendency to gain enough electrons to fill the shell Cl: 1s22s2p63s2p5 or [Ne] 3s2p5 Cl + 1e = Cl- negative ion (anion) Electropositive – if it is almost empty, it easily losses the electrons in the outer shell (typically metals) K: 1s22s2p63s2p64s1 or [Ar] 4s K – 1e = K+ positive ion (cation)
- 5. Types of chemical bonding 2 main types of chemical combination Ionic (or electrovalent combination) Covalent which is classed into 2 Ordinary covalent Coordinate covalent
- 6. Ionic bonding Typically between highly electropositive (metallic) and electronegative (nonmetallic) elements NaCl Na 1s22s2p63s Cl 1s22s2p63s2p5 Na+ 1s22s2p6 Cl- 1s22s2p63s2p6
- 8. Covalent bonding Takes place between elements with small difference in electronegativity - F, O, N, Cl, H, C, Si… s and p electrons are commonly shared to attain noble gas electron configuration Multiple bonds can be formed by one atom Eg in H molecule 2 H: 1s → H2 1s2 H· + H· →H : H (electron –pair covalent bond)
- 9. • O 2s22p4 • N 2s22p3
- 10. Other binding forces Metallic bond Van der waal’s Hydrogen bonds