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.
Answer:
Isotopes
Explanation:
Isotopes are atoms of the same element that contain an identical number of protons, but a different number of neutrons. Despite having different numbers of neutrons, isotopes of the same element have very similar physical properties.
Answer: IONIC EQUATION.
Explanation:
A chemical equation is defined as the form by which a chemical reaction is represented mathematically. These are written in the form of symbols and chemical formulas of reactants and products which are taking part in the chemical reaction. A chemical equation can be written in two forms, these include:
--> MOLECULAR EQUATION: in this type of equations, the compounds are written and represented in a molecular form. This is sometimes referred to as a balanced equation.
--> IONIC EQUATION: This is a type of chemical equation in which the electrolytes in aqueous solution are expressed as dissociated ions. A typical illustrated example is seen in the reaction between AgNO3(aq) and NaCl(aq) :
Ag+(aq) + NO3-(aq) + Na+(aq) + Cl-(aq) → AgCl(s) + Na+(aq) + NO3-(aq)
The (aq) written in the above equation signifies they are in aqueous solution.
MgBr2 is the chemical formula for magnesium bromide