An element's chemical properties depend on its valence electrons.The chemical properties of elements depend on an element's electron configuration.

Test tubes are convenient containers for heating small amounts of liquids or solids with a Bunsen burner or alcohol burner.

Pauli Exclusion Principle states that, in an atom or molecule, no two electrons can have the same four electronic quantum numbers.

Scandium has electronic configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{1}4s^{2}\) hence, \(Sc^{3+}\) has configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\). Hence, no electron in the 3d-orbital.

The various gases vaporize as their boiling points are reached, then they are pumped away and separately re-liquefied for convenient storage.

The purity of a solid can be determined by measuring the melting point. A pure solid will have a single, sharp melting point.

This is same as asking for the molar mass of the compound

= \((2\times 14.0)+ (8\times 1.0) + 12.0+(16.0\times 3)\)

= 28.0+8.0+12.0+48.0 = 96.0g

The orbital is a path or region around the nucleus. The electrons move in the orbitals and not through it.

The ionic radius decreases across a period but increases along a group.

This is caused by the increase in the number of protons and electrons across a period.