Answer:
a. BH₃
Explanation:
According to the octet rules, atoms reach stability when are surrounded by eight electrons in their valence shell when they combine to form a chemical compound.
From the options, the only compound in which the central atom does not meet the octet rules is BH₃. The central atom is boron (B), which has 3 electrons in its valence shell. When B is combined with hydrogen (H), 3 electrons from the 3 atoms of H are added. The total amount of electrons is 6, fewer than 8 electrons needed to meet the rule.
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<u>Answer:</u> The value of
for the given chemical reaction is 0.1415
<u>Explanation:</u>
Equilibrium constant in terms of partial pressure is defined as the ratio of partial pressures of the products and the reactants each raised to the power their stoichiometric ratios. It is expressed as 
For a general chemical reaction:

The expression for
is written as:

For the given chemical equation:

The expression for
for the following equation is:

We are given:

Putting values in above equation, we get:

The value of
for the given chemical reaction is 0.1415
They can be differnt shape or one must weight more then the other one
Neodymium is a chemical element with symbol Nd and atomic number 60.
Answer:
There are Seven periods in the periodic table