WJEC GCSE Chemistry Complete Practice Exam 2026

Alkali metals have one valence electron in their outermost shell, which is the electron they readily lose to form a +1 ion. This single outer electron sits in the highest energy level (the ns subshell), giving them the characteristic reactivity and chemistry of Group 1 elements. So the true statement is that there is one electron in the outer shell. The other options describe different groups: seven valence electrons would belong to halogens, eight would be a full outer shell like noble gases, and five doesn’t match the common valence of alkali metals.