What does the symbol in an electron dot diagram mean

Determine the age of a fossil if it had only one eighth of its original carbon-14 content remaining?

Amoving electron has kinetic energy k1. after a net amount of work w has been done on it, the electron is moving one-quarter as fast in the opposite direction. (a) find w in terms of k1. (b) does your answer depend on the final direction of the electron's motion?

Which of the following is not a means to accelerating? question 4 options: a)increase speed b)remain still c)decrease speed d)change direction