Important Laws

Question 1

Define the law of mass conservation

Answer 1

Mass in an isolated system can neither be destroyed or created by chemical reactions or physical transformations.

Question 2

Define the law of multiple proportions

Answer 2

When two elements or meolecules combine in more than one proportion to form two compounds, the weight of the elements are in the ratio of small whole numbers

Question 3

Define the principle of uncertainty

Answer 3

The concept tha precise, simultaneous measurements of some complimentary variables is impossible e.g position and momentum of electrons

Question 4

Define hund’s Rule

Answer 4

Every orbital in a sub-level is singly occupied before any orbital is doubly occupied

Question 5

Define the Aufbau Principle

Answer 5

In the ground state of an atom or ion, electrons fill the the lowest available energy levels in atomic orbitals

Question 6

Define the Pauli Exclusion Principle

Answer 6

There is a maximum of two electrons in one sub-level

Question 7

Define the octet rule

Answer 7

Metals and nonmetals form ions to achieve the electronic configuration of noble gases