* Poor conductors of heat and electricity: Non-metals are generally poor conductors of heat and electricity. Halogens are excellent insulators.
* Brittle in solid state: Halogens exist as solids, liquids, or gases at room temperature. When solid, they are brittle, which is a characteristic of non-metals.
* Low melting and boiling points: Compared to metals, non-metals tend to have lower melting and boiling points. Halogens generally have low melting and boiling points.
* Gases at room temperature: Many non-metals exist as gases at room temperature. Fluorine, chlorine, and bromine are gases at room temperature.
* Form acidic oxides: Non-metals tend to form acidic oxides when they react with oxygen. Halogens form acidic oxides.
* High electronegativity: Non-metals have high electronegativity, meaning they have a strong attraction for electrons. Halogens have the highest electronegativity values in their respective periods.
* Gain electrons in chemical reactions: Non-metals typically gain electrons in chemical reactions to achieve a stable electron configuration. Halogens have a strong tendency to gain one electron to form a -1 anion.
Overall, the properties of halogens demonstrate that they are non-metals, and they are classified as such on the periodic table.
