Chemistry · Ch 7 — Modern Periodic Table

Electronic Configuration in Groups

7.3.2

Electronic Configuration in Groups

Since a new outermost shell is added every time you step one period further down a group, the elements of a given group are generally expected to share the same general outer electronic configuration all the way down. This expectation holds cleanly for groups 1, 2 and 3 (see Table 7.1) and, in a slightly different sense, for groups 13 through 18: in these groups the intervening inner d and f subshells are already completely filled by the time the outer $ns$ / $np$ pattern is reached, so the GENERAL outer configuration again stays the same all the way down (Table 7.1 lists it for each group). The exception is groups 4 through 12, where the inner d subshell is only introduced starting at period 4, and the inner f subshell only starting at period 6 — so for the early periods of these groups (before the d, and later f, s …

Table 7.1General outer electronic configuration in groups 1-3 and 13-18 (Table 7.1)

Table 7.1 — general outer configuration and worked examples for each listed group:

Group 1: $ns^1$ — e.g. ₃Li: $2s^1$ , ₁₁Na: $3s^1$ .

Group 2: $ns^2$ — e.g. ₄Be: $2s^2$ , ₁₂Mg: $3s^2$ .

Group 3: $ns^2(n-1)d^1$ — e.g. ₂₁Sc: $4s^23d^1$ , ₃₉Y: $5s^24d^1$ .

Group 13: $ns^2np^1$ — e.g. ₅B: $2s^22p^1$ , ₁₃Al: $3s^23p^1$ .

Group 14: $ns^2np^2$ — e.g. ₆C: $2s^22p^2$ , ₁₄Si: $3s^23p^2$ .

Group 15: $ns^2np^3$ — e.g. ₇N: $2s^22p^3$ , ₁₅P: $3s^23p^3$ .

Group 16: $ns^2np^4$ — e.g. ₈O: $2s^22p^4$ , ₁₆S: $3s^23p^4$ .

Group 17: $ns^2np^5$ — e.g. ₉F: $2s^22p^5$ , ₁₇Cl: $3s^23p^5$ .

Group 18: $ns^2np^6$ — e.g. ₁₀Ne: $2s^22p^6$ , ₁₈Ar: $3s^23p^6$ . …

Start your 14-day free trial to unlock the full solution →

← Previous · 7.3.1Electronic Configuration in Periods Next · 7.3.3 →Electronic Configuration in the Four Blocks