Chemistry Assignment 1

1. What does an atom looks like?  What are the sub-atomic particles inside it.....(talk about electrons, neutrons, protons, electron shells, nucleus....)
Ans: An atom is made up of three different particles - protons, neutrons and electrons. Protons and neutrons are tightly packed together in the centre of an atom known as nucleus. Collectively,  protons which carry positive electric charge (+1) and neutrons which carry no electric charge are known as nucleons. Electrons which carry negative charge (-1) move rapidly around the nucleus on electron shells. Each electron shell must only contains 8 electrons, only the innermost shell contains 2 electrons.

2. Draw the atomic structure of a sodium atom and a sodium ion....explain why you draw it this way.
Ans:

The sodium atom was drawn according to the number of electrons it consists, the number of electrons also equals to the number of protons a sodium atom consists. However, a sodium ion has to lose one electron in order to complete its valence shell so as to make it stable, therefore, there will be one more proton than electron.

3. Draw the atomic structure of a sulfur atom and a sulfide ion....explain why you draw it this way.

Ans:

The sulfur atom was drawn according to the number of electrons it consists, the number of electrons also equals to the number of protons a sulfur atom consists. However, a sulfide ion has to gain two electrons in order to complete its valence shell so as to make it stable, therefore, there will be two less proton than electron.

4. Chlorine-35 atom and Chlorine-37 atom are called isotopes...Use these two examples to explain what is 'isotopes'

Ans: Chlorine-35 have 17 protons and 18 neutrons. Chlorine-37 have 17 protons and 20 neutrons.They have the same number of protons, however, they have different number of neutrons, 18 and 20 neutrons respectively. hence, they are isotopes.

5. Sodium is a metal and sulfur is a non-metal....why we classify them this way??

Ans: Metals conduct heat and electricity, and sodium has these properties, thus, sodium is a metal. Non-metals do not conduct heat and electricity, and sulfur has these properties, thus, sulfur is a non-metal. Sodium is being classify in Group(I) as it loses one electron to become an ion whereas sulfur is being classify in Group(VI) because it gains two electron to become an ion.