Octet rule, achieving it
- An atom becomes more stable as its electron configuration becomes like that of a noble gas.
- Octet rule = atoms tend to combine in such way that they have 8 e in their valence shell, giving them the same electronic configuration as that of a noble gas.
Atoms can achieve it by gaining, loosing or sharing e
Ionic bond, their properties
- is formed between positive and negative ions.
- Ionic compounds have high melting and boiling points, they dissolve in polar solvents (such as water)
Lewis electron dot diagram
represent the valence shell of an atom
- made by sharing pairs of electrons.
- Ex. Cl2
- Compounds can have single, double or triple covalent bonds
- Dipoles attract each other, other dipoles, and ions, they have higher melting and boiling points than non-polar molecules
Types of covalent bond
- 1) Polar covalent bond
- atoms share electrons unequally => electrons are being held closer to one atom than to the other (HCl)
- electrons are held closer to the Cl than to H
- This makes Cl side of molecule slightly positive and H side of molecule slightly positive => DIPOLE
- 2) Non-polar covalent bond
- when atoms share electrons equally (cl2)
When a molecule has a polar covalent bond, and one of its sides are slightly positive and other is negative, such molecule called dipole (two poles)
- solvents that are dipole
- ex: water = have surface tension and capillary action