Periodic Table of the Elements

Question 1

Classify elements on the basis of their macroscopic proerties?

Answer 1

Solid a state of matter with a definite shape and volume

Liquid a state of matter that has no fixed shape but takes shape of its container, has a definite volume and consist of atoms or molecules that are connected by intermolecular bonds

Gas a state of matter that has neither defined volume nor shape

Aqueous is a solution with water as the solvent

Question 2

What is natural elements?

Answer 2

Natural elements that occur naturally on earth: e.g., Aluminium, Argon, Boron, Calcium, Carbon, Fluorine, Iodine Hydrogen.

Question 3

What is unnatural elements?

Answer 3

Unnatural elements are a synthetic element, which is chemical elements that do not occur naturally on Earth. They are created by human manipulation of fundamental particles in a nuclear reactor, a particle accelerator, or the explosion of an atomic bomb. Unstable and radioactive in nature

Question 4

Explain what adundant means and identify the most abundant in the universe and biological systems?

Answer 4

To be used by biological systems, elements must be abundant in the environment and in an easily extractable form

The lighter the element are the most abundant in the Universe and on Earth.

When elements show similar properties and can play similar biological roles, the most abundant in the crust/oceans/
atmosphere are selected

Examples Na, K, Mg and Ca are preferred over Li, Rb, Cs, Be, Sr and Ba.

Question 5

Discuss the factors benefiting carbon-based Life on Earth

Answer 5

Versatility in Bonding
Chain Formation and Stability of Carbon Compounds
Energy Efficiency
Carbon’s Abundance in the Universe
Water Solubility
Lightweight Element

Question 6

Define the concept of element?

Answer 6

A pure chemical substance composed of atoms with the same number f protons in the atomic nucleus

An element is defined as a single, simple substance that cannot be split into more separate substances by chemical means

Question 7

Describe proton?

Answer 7

Proton = Carry positive charge and have a mass of 1 atomic mass unit which is approximately
1 ×10^(-27) kg

Question 8

Describe neurons?

Answer 8

Neutrons = They are not charged and have a mass of 1 atomic mass unit which is approximately
1 ×10^(-27) kg

Question 9

Define electron?

Answer 9

Electrons = Carry negative charge and have a mass of approximately
9.11 ×10^(-31 ) kg

Question 10

Define the term atomic number?

Answer 10

Number of protons in the nucleus

Question 11

Define the term mass number?

Answer 11

mass of the protons and the neutrons in the nucleus

Question 12

Identify isotopes of main group elements

Answer 12

(_6^12)C (98.9%) and (_6^13)C (1.1%)

(^10)B (19.9%) and (^11)B (80.1%)

(^14)N (99.6%) and (^15)N (0.4%)

(_17^35)Cl (75%) and (_17^37)Cl (25%)

Question 13

How to calculate the relative atomic mass of elements?

Answer 13

Ar = (total mass of
atoms )/(total number of
atoms )

e.g
(75x35)+(25x37)/(75+25) = 35.5