Metals and Non-Metals
* Metals are elements that have a tendency to lose electrons and form positively charged ions or cations.
* Elements that have a tendency to accept electron to form negatively charged ions or anions are called non- metals.
* Metals are placed on the extreme left in the periodic table, while non-metals are placed on the extreme right in the periodic table.
* Metals are solids, malleable, ductile, and lustrous with high melting and boiling points.
* Non-metals are electronegative, bad conductors of heat and electricity, from acidic oxides which are covalent.
* Electrolysis is a process of decomposition of an ionic compound by passing electricity through it.
Carbon and its Compounds – Bonding in Carbon
* Covalent compounds have low melting and boiling points.
* Carbon achieves stability by sharing electrons.
* Bonds formation is represented using Lewis structures.
* A shared electrons pair is known as bond pair.
* A single covalent bond ifs formed by sharing a pair of electrons.
* A double covalent bond is formed by sharing two pair of electrons.
* A triple covalent bond is formed by sharing three pair of electrons.
* In a methane molecule, the carbon atom shares electrons with four hydrogen atoms.
Why do Atoms Combine
* The atoms of the elements of the 18th group have minimum energy, and are highly stable among all the elements.
* The presence of two electrons in the first shell, called a duplet configuration, or eight electrons in the valence shell, called an octet configuration, is collectively referred to as inert gas configuration, which is the most stable electronic configuration.
* In the formation of sodium chloride, sodium loses one electron to form a sodium ion, and attain the nearest inert gas configuration of neon. Chlorine gains one electrons to form a chloride ion, and attains the nearest inert configuration of argon.
* Atoms of elements such as chlorine and oxygen attain stability by sharing electrons, and form molecules.
* The number of electrons lost, gained or shared by an atom of an element during a chemical reaction for attaining stable electronic configuration is called valency.
