Lesson 2

Hey guys! Daddy's home!:P oh yeah, alright back to business. Today, it is lesson 2 and I shall start now.

What is isotopes?

Isotopes are atoms of the same element with the same number of protons BUT different number of neutrons.

Examples: Carbon has 3 isotopes : carbon - 12, carbon - 13 and carbon - 14

Electronic configuration

-the way the electrons are arranged in an atom is called the atom's electronic structure or electronic configuration.

Examples: Nitrogen has 7 electrons.

Electronic configuration would be : 2.5

Argon has 18 electrons.

Electronic configuration would be : 2.8.8

Valence Shell

-the furthest occupied shell from the nucleus

Valence Electrons

-electrons in the valence shell

Note : ONLY valence electrons are in involved in chemical reactions.

Before we go to another topic, I got a little test for you.

-Describe how the elements in the periodic table are arranged.

Ans: The arrangements of the elements are arranged in an order of increasing proton( atomic) number.

Formation of ions

-During chemical reactions, some atoms might lose/gain electron(s). An atom becomes an ion(charged particle) when it lose/gain electron(s).

Alright, use the concept of what I had just written and think about this question :

Why does an atom become a charged particle when it gains or loses electron(s)?

-Ans : When an atom loses of gains electron(s), the positive and negative charges are not balanced. And therefore, the atom becomes a charged particle.

Formation of Cations

-When an atom loses 1 or more electrons, it becomes a positively charged particle called cation.

Example : Lithium atom(Li) Lithium ion(Li+)

3 protons 3 protons

3 electrons 2 electrons

Net charge : 0 Net charge : +1

Formation of Anions

-When an atom gains 1 or more electrons, it becomes a negatively charged particle called anion.

Example : Fluorine atom(F) Fluorine ion(F-)

9 protons 9 protons

9 electrons 10 electrons

Net charge : 0 Net charge : -1

You might be wondering why atoms become ions?? WHY??

Ans : To obtain a full valence shell

-To obtain the same electronic structure of a noble gas so as to be stable. ( Note : Nobel gas will be covered in the next lesson)

Alright, I hope you have learnt some new concepts such as what is cations and anions. Try to understand the concepts and do not hesitate to ask me if you have any doubts. ENJOY!:D