Answer:
B) Their valence shell is full
Explanation:
In order to be classified as a noble gas, an element must have a complete octet/ a full shell of valence electrons, as shown in answer B.
A and C are just incorrect. Since noble gasses are very unstable, D is a true statement, but is isn't the correct answer as this does not explain why they are inert.
<h3>Hope this was helpful!</h3>
Answer:Number of electrons that are present in an atom is determined by the electronic configuration of that atom.
If an ion is carrying a positive charge, it means that the atom has lost electrons and if an ion is carrying a negative charge, it means that the atom has gained electrons.
For the given options:
Option A: The atomic number of hydrogen atom is 1 and the electronic configuration for ion will be:
Thus, this atom does not have any electrons.
Option B: The atomic number of bromine atom is 35 and the electronic configuration for ion will be:
Thus, this atom has 36 electrons.
Option C: The atomic number of aluminium atom is 13 and the electronic configuration for ion will be:
Explanation:
Remember that:
number of moles = mass/molar mass
First, we get the molar mass of the nitrogen gas molecule:
It is known the the nitrogen gas is composed of two nitrogen atoms, each with molar mass 14 gm (from the periodic table)
Therefore, molar mass of nitrogen gas = 14 x 2 = 28 gm
Second we calculate the mass of the precipitate:
we have number of moles = 0.03 moles (given)
and molar mass = 28 gm (calculated)
Using the equation mentioned before,
mass = number of moles x molar mass = 0.03 x 28 = 0.84 gm
The oxidation number of H is -1.
Sum of the oxidation numbers in each element =
charge of the complex
CaH₂ has 1 Ca atom and 2H atoms. The charge of
the complex is zero. Let’s say Oxidation number of H is "a".
Then,
<span> (+2)
+ 2 x a = 0 </span>
<span> +2 + 2a = 0</span>
2a = -2
a = -1
Hence, the oxidation number of Hydrogen atom in CaH₂ is -1
