Which of the following atoms is least likely to form chemical bonds with other atoms
a. a hydrogen containing 1 valence electron
b. a carbon atom containing 4 valence electrons
c. a neon containing 4 valence electrons
d. a sodium atom containing 1 valence electron

Two particles of masses m and 2m are placed on a smooth horizontal table. a string, which joins these two masses, hangs over the edge supporting a pulley, which suspends a particle of mass 3m. the pulley has negligible mass. the two parts of the string on the table are parallel and perpendicular to the edge of the table. the hanging parts of the string are vertical. find the acceleration of the particle of mass 3m.

With i really need the correct answer!

If steel is more dense that lake water, why can a boat float