Lewis diagram:
well first you have to know the Valence electrons the elements which will on top of the periodic table.
for examples:
H2O
it will be O-H-O and the dots will on top. oxygen have 6 valence electrons so that mean it need 6 dots. also for H it will have 7 V-electrons.
Magnesium and I think its MG12 for the other part
That photon's energy is equal to Planck 's constant, multiplied by the light frequency, h is always 6.63* 10^ -34 Joule seconds and the frequency is 6* 10^ 14 Hz.
Since the container of the gas is rigid, the volume of the gas will remain constant. Therefore, when the number of particles were decreased in half then the pressure will also be half of the original given they both are subjected to the same temperature.
PV = nRT
V, T and R are constants so they can be lumped together to a constant k.
P/n = k
P1/n1 = P2/n2
since n2 = n1/2
P1/n1 = P2/<span>n1/2</span>
P2 = P1/2
My guess is b for the question