My term 1 test

Hey guys! Today, there will not be any lessons!! YAY!! haha oh back to the point, hmm, today I will be sharing with you guys about my science test.

How shall I begin with? Hmm, well, I have to admit that I did not revise a lot to prepare myself the test. Well, quite a few of the mistakes I had make in the test paper were concepts taught in the power point and I did not go and revise it. And you see, science can be easy as all you need to do is to memories the concepts of what you had learn because they are facts and they cannot be change. Back to reflection, through this test, I have learnt my lesson. I need to put in more effort in my science as it can really pull down my whole grades. It is NOT because it is counted in my grades and I study science for the sake for studying it. Science is going to be somehow useful to me in my daily life.

Guys, if you have done well in your science test then EXCELLENT JOB!! Keep it up!! For those who did poorly or not as good you wanted, learn from your mistakes and pick yourself up!! Do approach me if you have any doubts!!:D

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

Lesson 1

Hey guys!! Well today, I shall start my lesson officially. Alright, back to business, today I will be teaching you guys what is atomic structure.

Remember??

An atom is the smallest unit of an element, having the properties of the element.

Now, think about this. Are atoms small solid balls with nothing inside??

Ans : No. Why no?? Well, we are going to answer that question through this question.

Atoms -- made up of subatomic particles ( refer to the top image)

Particle Symbol Relatively mass Charge

Proton P 1 1+

Neutron N 1 0

Electron E 1/1836 1-

Wait a second, why is the term "relatively mass" used rather than the term just mass?

Before you can answer the question, let me give you some hints :

Mass of of proton =~1.67x10-27 kg.

Mass of neutron =~1.67x10-27 kg.

Mass of electron =~9.11x10-31 kg.

Well, mass of proton, neutron and electron are too small and inconvenient to work with and thus by using relative mass, we do not have to remember to the exact value of the various masses.

Proton number

-the number of protons in an atom is called the proton number. It is also be known as the atomic number.

To count the number of neutrons in an atom,

Firstly, you have to understand what is Nucleon number.

Nucleon number

-nucleon number is the number of protons and neutrons in the nucleus of an atom.

-it is also called as the Mass number.

Nucleon number (Mass ) number = neutrons + protons

The center of an atom is called the nucleus and it contains the number of protons + number of neutrons.

Electrons

As you all know that electron is a negative charge, now as you can refer from the top picture, electrons are arranged in shells (orbits) at different distances from the nucleus.

Note : Shells are also called energy level.

Each shell can hold a certain maximum number of electrons of.

(a) 1st shell : 2 electrons

(b)2nd shell : 8 electrons

(c) 3rd shell : 8 electrons (the 1st twenty elements)

Now, let me give you a little test.

Why is an atom electrically neutral?

Number of electrons = number of protons. Equal positive and negative charges.

However, why is the nucleus positively charged?

The nucleus contains protons and neutrons. As protons are positively charged while neutrons are electrically neutral, and thus the nucleus is positively charged.

Alright, that's all for today's lesson. Well, go and digest what I had taught here and be prepared for the next lesson!:D