All alkali metals have ______melting and boiling points

Give Reason. Most of the transition metals have high melting point and boiling point.

Give reason : (i) Most of the transition metals have high melting point and boiling point (ii) 2^(nd) ionization enthalpy of Cu is exceptionally high. (iii) atomic size of 4d- and 5d-series elements are almost the same.

(i) "Covalent compounds have low melting and boiling points". Justify this statement. (ii) What is an ester ? Describe an activity to form an ester in a school laboratory.

Transition metals are very hard and have high melting and boiling points. Give reason.

State the reason why carbon forms a covalent compound and not C^(4+) and C^(-4) . Also give reasons why covalent compounds are bad conductors of electricity and have law melting and low boiling points.

Which of the following has highest melting and boiling points?

Give reason for the following : (i) Ionic compound have high melting and boiling points. (ii) Ionic compounds are soluble in water. (iii) Ionic compounds conduct electricity in molten state.

Give reasons for the following : (i) Metals are good conductors of electricity whereas non-metals are not. (ii) Ionic compounds have usually high melting and boiling points.