Answer: A/40 it is actually 39.997 but since that is not an answer they rounded up
Explanation:
The atomic number is 9 Ions have the same atomic number since atomic number signifies number of protons not electrons
The test for this is fairly simple.
We take a glowing match or splint near the gas sample, if the glow intensifies, oxygen is present.
If a lit splint or match goes out with a popping sound, this means that hydrogen is present.
There are five states of matter out of which we encounter three states of matter in our day today life
a) gas b) solid and c) liquid
the main difference between the three is of
a) Inter molecular forces of attraction
b) thermal energy
due to this
a) solid has high intermolecular forces and low thermal energy: thus they have fix shape and occupy fix volume
b) liquid has intermediate forces and medium themal energy. Thus they may have fixed volume and but no fix shape
c) gas has weak intermoelcular forces and high thermal energy. thus they have no fixed volume no fix shape
so in the given problem
the state of the substance D- Gas.
