What's the problem ? Hardness is not the definition of a metal.
You need to expand your thinking. EVERY element is solid, liquid, and gas, over different ranges of temperature ... including all of the metals. There are only TWO elements that are liquid AT ROOM TEMPERATURE, and mercury is one of them. But on a mild day at the south pole, mercury is solid too.
Because when equilibrium is reached, the reaction is still occurring in both directions, it's just that rate(forward) =rate(reverse) so there is no net change in the concentrations of the reactants or products.
Answer:
The central atom has 3 electron domains.
Explanation:
According to the Valence Shell electron pair repulsion theory (VSEPR) put forward by Gillespie and Nyholm in 1957, the shape of a molecule is determined by repulsion between all the electron pairs (electron domains) present in the valence shell.
The electron pairs or electron domains are known to position themselves as far apart in space as possible in order to minimize repulsions.
Hence, when the central atom of a molecule contains three electron domains, they are positioned at an angle of 120° from each other to minimize repulsions. Hence the answer.
