I'd guess A or D, but my gut says A
Answer:
a. Be and Mg
Explanation:
Be (beryllium) and Mg (magnesium) are both found in the alkaline earth metals family (group 2) on the periodic table. Elements in the same family or group have similar properties,
Ca and Br are in groups 2 and 17
Cl and Ar are in groups 17 and 18
Na and P are in groups 1 and 15
Answer:
There was 450.068g of water in the pot.
Explanation:
Latent heat of vaporisation = 2260 kJ/kg = 2260 J/g = L
Specific Heat of Steam = 2.010 kJ/kg C = 2.010 J/g = s
Let m = x g be the weight of water in the pot.
Energy required to vaporise water = mL = 2260x
Energy required to raise the temperature of water from 100 C to 135 C = msΔT = 70.35x
Total energy required = 

Hence, there was 450.068g of water in the pot.
Answer : The energy of the photon emitted is, -12.1 eV
Explanation :
First we have to calculate the
orbit of hydrogen atom.
Formula used :

where,
= energy of
orbit
n = number of orbit
Z = atomic number of hydrogen atom = 1
Energy of n = 1 in an hydrogen atom:

Energy of n = 2 in an hydrogen atom:

Energy change transition from n = 1 to n = 3 occurs.
Let energy change be E.

The negative sign indicates that energy of the photon emitted.
Thus, the energy of the photon emitted is, -12.1 eV