What type of ion do elements from Group 1 form?

Elements from Group 1 of the periodic table, known as alkali metals, have one electron in their outermost shell. In order to achieve a stable electronic configuration, these elements tend to lose that single electron during chemical reactions. By losing one electron, they become positively charged ions, known as cations.

When an atom loses an electron, the number of protons in the nucleus remains unchanged, leading to an excess of positive charge relative to the negative charge from the electrons. For example, lithium (Li) can lose one electron to become Li⁺, and sodium (Na) can lose an electron to become Na⁺.

This characteristic of forming positive ions is a key defining feature of the alkali metals and explains their high reactivity, as they readily interact with other elements to form compounds. This behavior is not applicable to the other options mentioned, which do not accurately describe the nature of ions formed by Group 1 elements.