Berapa massa atom rata-rata lithium?

Massa atom Li ⁶ = 6,0151μ

Massa atom Li ⁷ = 7,0160μ

Persentase kelimpahan Li ⁶ =8,24%=0,0824

Persentase kelimpahan Li ⁷ = 92,70 = 0,9270

Untuk menghitung massa masing-masing isotop masing-masing

massa atom rata-rata= Persentase kelimpahan isotop×massa atom isotop 1+Persentase kelimpahan isotop 2×massa atom isotop 2

massa rata-rata litium=0,0824×6.0151μ+0.9270×7.0160μ

=0,4956μ+6,5038=6,9994μ

Massa atom rata-rata lithium adalah 6,9994μ

5