THE PERIODIC TABLE

Question 1

Element

Answer 1

a substance which cannot be split into simpler substances by chemical means.

Question 2

Dobereiner’s Triads

Answer 2

groups of three elements of similar chemical properties in which the atomic weight of the middle element is approximately equal to the average of the other two.

Question 3

Newland’s Octaves

Answer 3

are groups of elements arranged in order of increasing atomic weight, in which the first and eight element of each group have similar properties.

Question 4

Mendeleev’s Periodic Law

Answer 4

When elements are arranged in order of increasing atomic weight, the properties of the elements vary periodically.

Question 5

Atomic Number

Answer 5

of an atom is the number of protons in the nucleus of that atom.

Question 6

Modern Periodic Law:

Answer 6

When elements are arranged in order of increasing atomic number, the properties of the elements vary periodically.

Question 7

Mass number

Answer 7

of an element is the sum of the number of protons and neutrons in the nucleus of an atom of that element.

Question 8

Isotopes

Answer 8

atoms of the same element, with the same atomic number, but different mass numbers due to the different number of neutrons in the nucleus.

Question 9

Relative Atomic Mass

Answer 9

The average of the mass numbers of the isotopes of the element, as they occur naturally, taking their abundances into account. Expressed on a scale in which the atoms of the carbon 12 isotope have a mass of exactly 12 units.

Question 10

Mass Spectrometer:

Answer 10

Vaporisation, Ionisation, Acceleration, Separation, Detection.

Question 11

Aufbau Principle

Answer 11

states that when building up the electronic configuration of an atom in its ground state, the electrons occupy the lowest available energy level.

Question 12

Hund’s Rule of Maximum Multiplicity

Answer 12

states that when two or more orbitals of equal energy are available, the electrons occupy them singly before filling them in pairs.

Question 13

Pauli Exclusion Principle

Answer 13

states that no more than two electrons may occupy an orbital and they must have opposite spin.

Question 14

Atomic radius

Answer 14

of an atom is defined as half the distance between the nuclei of two atoms of the same element that are joined together by a single covalent bond.

Question 15

First ionisation energy

Answer 15

of an atom is the energy required to completely remove the most loosely bound electron from a neutral gaseous atom.