Introduction to the periodic table

01 Feb Introduction to the periodic table

Chemistry tuition classes in Miracle Learning Centre are easy to understand and help you in the chemistry tuition application questions. If you do not understand chemistry in school, you must definitely come for chemistry tuition classes at Miracle Learning Centre. Let us learn about the periodic table in this chemistry tuition lesson.

A periodic table consists of groups which are the vertical columns, and periods which are the horizontal rows. We will now look at the trends in the periodic table.

The elements in the periodic table are arranged in order of increasing proton number. The elements on the left hand side are metals and the elements on the right hand side are non-metals. There is a progression from left to right from metals to non-metals. The oxides from left to right also change in properties from basic oxides to amphoteric oxides to acidic oxides to neutral oxides.

For elements down the group, the size of the atom increases due to an increasing number of electron shells. Across the period, the number of shells remains the same but there is an increase in the number of protons and electrons, hence there is an increase in electrostatic force of attraction between the protons and electrons. Across the period, the size of the atom decreases.

As we look at Group I, since the size of the atom increases down the group, the reactivity of the metals increase down the group as well. Why is this so?

Metals lose electrons if they have 1, 2 or 3 electrons in their outermost shell. Hence to obtain a noble gas electronic configuration, it is easier for them to lose electrons to obtain a noble gas structure. For Group I metals, they need to lose 1 electron to obtain a noble gas electronic configuration. Hence for Group I metals, it is easier to lose an electron as we move down the group because the size of the atom increases. As the size of the atom increases, the electrostatic force for the valance electrons decrease as the distance of the valence electron from the nucleus increases. Hence it is easier to lose an electron. Therefore the reactivity of the metals increases down Group I.

For Group VII, non-metals gain electrons. Fluorine gain electrons most easily as it have the smallest atom. Hence the most reactive non-metal in Group VII is fluorine. Reactivity decreases down the group as it gets harder and harder to gain electrons as the size of the atom increases down the group.

The student at Miracle Learning Centre asked, “Why do we need to learn about the periodic table?”

Mrs Lew, chemistry tuition teacher at Miracle Learning Centre replied, “As we learn about the trends in a periodic table, we are able to identify how each element react based on the group they are in. Elements in the same group have the same number of valence electrons hence they possess similar chemical properties. For example if we know lithium reacts with water, we also know that caesium and rubidium can react with water as well. This is because they are all in the same group and they possess similar chemical properties.”

Miracle Learning Centre aims to educate students about what is the periodic table. Do come to Miracle Learning Centre for more chemistry tuition lessons to learn more about the periodic table.

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