Chapter 4:The Periodic Table(Definitions)

Question 1

What is an element (1)

Answer 1

-an element is a substance that cannot be split into simpler substances by chemical means

Question 2

What is a triad (2)

Answer 2

• a group of three elements with similar chemical properties
• in which the atomic weight(relative atomic mass) of the middle element is approximately equal to the average of the other two

Question 3

What is Newland’s Octaves (1)

Answer 3

-arrangements of elements in which the first and the eight element, counting from a particular element, have similar properties

Question 4

What is Mendeleev’s Periodic Law (2)

Answer 4

• when elements are arranged in order of increasing atomic weight (relative atomic mass)
• the properties recur periodically

Question 5

What is an atomic number

Answer 5

-the number of protons in the nucleus of that atom

Question 6

What is the modern periodic table (1)

Answer 6

-an arrangement of elements in order of increasing atomic number

Question 7

What is modern periodic law(2)

Answer 7

• when elements are arranged in order of increasing atomic number
• the properties of the elements recur periodically

Question 8

What is a mass number (1)

Answer 8

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

Question 9

What are isotopes

Answer 9

• atoms of the same element which have different mass numbers
• due to the different number of neutrons in the nucleus

Question 10

Define relative atomic mass(4)

Answer 10

• the average of the mass numbers of the isotopes of the elements
• 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 11

Define the principle of mass spectrometry (4)

Answer 11

• charged particles moving in a magnetic field
• are deflected to different extents
• according to their masses
• and are thus sperated according to these masses

Question 12

Define electron configuration (1)

Answer 12

-the arrangement of electrons in an atom of an element

Question 13

Define the Aufbau Principle(2)

Answer 13

• when building up the electron configuration of an atom

- in it’s ground state, the electrons occupy the lowest available energy levels

Question 14

Define Hund’s Rule of Maximum Multiplicity(2)

Answer 14

• when two or more orbitals of equal energy are available,

- the electrons occupy them singly before filling them in pairs

Question 15

Define Pauli’s Exclusion Principle (2)

Answer 15

• no more than two electrons may occupy an orbital

- and they must have opposite spin