(N/A) Elements are classified into metals,non-metals,and metalloids based on their physical and chemical properties.
$1$. Metals: Metals constitute more than $78 \%$ of all known elements and are located on the left side of the periodic table. They are typically solids at room temperature,with $Hg$ being an exception. Metals generally have high melting and boiling points,are good conductors of heat and electricity,and are malleable and ductile. Metallic character increases down a group and decreases across a period from left to right.
$2$. Non-metals: These are situated on the top right side of the periodic table. They are usually solids or gases at room temperature with low melting and boiling points (except $B$ and $C$). They are poor conductors of heat and electricity (except graphite) and are brittle. Non-metallic character increases across a period from left to right and decreases down a group.
$3$. Metalloids (Semi-metals): These elements exhibit properties of both metals and non-metals. Elements like $Si$,$Ge$,$As$,$Sb$,and $Te$,which lie along the diagonal boundary between metals and non-metals,are classified as metalloids.