2011 Term 1 Reflections

I find Secondary 2 a lot harder than Secondary 1. At the start of the year, I had difficulties understanding what is being taught. In Term 1, I learned more about chemistry. I learned about the atomic structure, ionic and covalent bonding and also word equations. As it was a new topic to me, at first I found it quite hard to understand, however, after many practices and help from my friends, I finally managed to understand most of it. I find that word equation is quite tough as it needs you to understand very well and also need a lot of practice. As for the term test, I think I did not so badly. However, there is still lots of room for improvement as I need to improve on the word equations. Until now, I still have some problems doing word equations hence this means that I would need to work double hard on that area.

Periodic Table

We learnt about the periodic table and the elements in this term. There are 8 groups in the periodic table. They are grouped according to their properties and the number of valence electrons they have. Group 1 and 2 are metals and group 8 is noble gases. The period are grouped according to the number of filled electron shells it have and also it increases in the number of valence electrons as the elements moves from left to right.

The number " 16 " on top is the mass number. The mass number is made up of the number of protons plus the number of neutrons. Isotopes are atoms from the same element and have the same number of protons and electrons but have different number of neutrons. The number " 8 " below is the atomic number. It is the number of protons the atom has. Normally, the number of protons would also be the same as the number of electrons. Ions are atoms when the number of electrons is not the same as the number of proton hence it would either be positive if it loses an electron or negative if it gains an electron.

Ionic Bonding and Covalent Bonding

Ionic bonding is a chemical bond between a non-metal and a metal. Metal would have lesser valence electrons and non-metal would have more valence electrons. Hence in order to get a full shell like the noble gases to be more stable, metal would lose its electrons, becoming positive, and non-metal would gain electrons, becoming negative. This process is called ionic bonding. Examples of ionic bonding are Na and Cl. Na would lose an electron and Cl would gain an electron to be able to form a stable full shell.

Covalent bonding is a form of chemical bonding between two non-metals. The two non-metals share their electrons to be able to have a stable full shell like the noble gases. Examples of covalent bonding are two hydrogen atoms. They have one atom each and hence would share with each other in order to have a complete shell of two electrons. This process is covalent bonding.