Atoms and Periodic Table of Elements

TECHNOLOGY

By MICHAEL JOHN UGLO
WE are into the very first lecture in this series of lectures on Matter. Prior to delving into the subject at hand, it must to said that the nation of PNG has to have a sense of belonging to a community than to live as if nobody is living close to them and needs their attention and cooperation. This should be the virtual binding factor that can bring this country into greater breadths and heights of prosperity.
Having regards for one another despite any wrongdoing and hatred that there may have been. This is the way of progress as they say divide and be ruled or alternatively being united we stand. The case in point is, see that China is converting millions of its population of peasants and farmers into factory workers and wage earners almost everyday. The tiny eight million plus population of PNG can do that without self-ambitious and prideful living and incompetent leaderships prevalent in this nation.
Atoms and the Periodic Table of Elements
All things in the world and the universe is made of matter. Matter can be defined as anything that takes up space and has mass. Matter appears in solid, liquid, gas and a fourth substance called the plasma. Plasma is an ionized gas that is a fluid of positively charged matter surrounded by a sea of electrons. This sort of matter is found where the heat is so intense to ionize or displace the electrons from the known gases and to cause it to be in this form. All these forms of matter are made of a building block called the atoms. Thus, atoms are the indivisibly pure substance of any element found on earth and in the universe.
With matter being everything on earth and in the universe, we can investigate their particle or the atomic arrangements for the solids, liquids and the gasses. Matter can appear as mixtures or as compounds. Mixtures are substances which are just combined and not chemically bonded while compounds are chemically bonded. Mixtures are of two types. These are homogenous and heterogenous mixtures. The homogenous mixtures contain only one substance. An example can be pure water without anything added to it. It can also be refined or pure copper or even gold. Another kind of mixture is the heterogenous mixture and this can contain a mixture of more than two substances. Two examples are the gasses in the atmosphere which contains many gasses like oxygen, nitrogen, water vapor, hydrogen, carbon dioxide and so on. The other example is the sea or the saline water. The sea and oceans contain a mixture of dissolved salts such as sulphates, carbonates, nitrates chlorides which are just mixed together with water. That is the reason for marine water to taste salty. Unlike mixtures, matter can also appear as compounds whose individual elements are chemically bonded.
Compounds have new and different properties form their parent composition and behave differently while mixtures do not have new properties but show the same characters of their parent composition. Melting point of a substance is lowered when there are impurities in it. The more impurities mean their melting point is even less. The boiling points are increased in substances that have impurities in it and the more impurities the more increased their boiling point is.
The vapor pressure of water determines its boiling point. The evaporation of water results when its vapor pressure is equal to the atmospheric pressure. If impurities are added such as the salt water it would not boil at 1000C but will require more heat so the boiling point will be much higher than 1000C.

The method in which cells of plants and animals obtain water in and out of them is through a process called osmosis. This is diffusion of solvent across a semipermeable membrane where water flows from a concentration gradient of less to more concentration. It is expected that the inner part of the cell is more concentrated with the glucose in the case of plants and blood sugar in the case of animals.
Atoms of one element are different from elements of another element. For instance, the atoms of oxygen are different from the atoms of nitrogen or even sodium or calcium. Atoms are made up of three subatomic particles called electrons, protons and neutrons. The electrons carry negative charges, while the protons carry positive charges and the neutrons carry no charges.
The different kinds of elements with their different number of protons, electrons and neutrons allows for them to be properly arranged into a table. This table is called the Periodic Table of Elements. Periodic table of elements was pioneered by a Russian person who studied chemistry or a chemist by the name of Mendeleev. He found elements which he arranged in the periodic table and the missing ones he predicted that these were there in nature according to the atomic and mass numbers and his predictions were correct. They were able to fit all these elements into the periodic table according to their increasing atomic numbers. Hence, the periodic table of elements is arranged in the order of increasing number of protons also known as atomic number as advocated by Mendeleev. The periodic table of elements’ columns are known as Groups and the rows are known as the periods. The number of protons in an atom of an element are called the atomic numbers. The number of protons and electrons are the same because they carry equal opposite charges to produce the neutral atom. So atomic number is actually referred to the number of protons simply because there are much heavier than the electrons mass which is almost negligible. Likewise, the number of protons together with the number of neutrons combined is called the mass number. The groups are labelled from one to eight according to the number of electrons they have on their outer most shell called the valence electrons. The group one elements are also called alkali metals and have only one electron or one valence electron in their outer most shells. The group two elements have two valence electrons in their outer most shells and are also called the alkaline earth metals. Group three elements have three valence electrons in their outer most shells.
The group four elements are called the transition metals because they have four valence electrons in their outer most shells. There are like sitting on the fence. Group five elements, group six elements, the group seven elements and the group eight elements have respectively five, six, seven and eight valence electrons in their outer shells. Group seven elements are called halogens. Group eight elements are called inert or noble gasses. The reason is that they have a full eight electrons in their outer most shell referred to as them having a full octet shell. That makes the group eight electrons become inactive or become inert.

The group one to group three elements are metals while the group five to seven elements are non-metals. The group eight elements are noble or inert gasses because the not reactive since they have a full octet shell. Every element in the periodic table has its different atomic number as well as its mass number.
Unlike atomic numbers, mass numbers are the number of protons and neutrons combined and that is the number of their net mass. The two numbers which are the atomic numbers and mass numbers are always written together with the element. Mass number is bigger than the atomic number because mass number includes both number proton plus the number of neutron while the atomic number is only the number of protons. We say relative atomic number because elements in nature also have their isotopes. Isotopes of elements are those same elements of the same atomic numbers but they have different mass numbers. That is why, the relative abundance of that element of greater quantity is chosen to represent that element. For instance, there are three isotopes of hydrogen known as hydrogen (H), deuterium (H2) and tritium(H3). The one with the greater relative abundance in percentage is H so this is taken to represent all hydrogen isotopes.
An example of a mass number and an atomic number of an element is, say for Carbon it is twelve and six respectively. So, in the periodic table it will be written as 126C. That is, the 12 is carbon’s mass number and the number 6 is carbons atomic number or the number of protons which also implies the number of electrons because these are of the same size and that is, 6 protons and 6 electrons. When we have 12 as our mass number, we can know that the number of neutrons is also 6.
Therefore, we know that the atomic number is six so the neutron number must also be six to give the mass number 12.
The transition metals are group four and are in the middle because they act as metals as well as non-metals because of their four valence electrons. That is, they change their chemical properties under different circumstances. Sometimes they act as metals and at other times they act as non-metals as suggested by the name transition.
My prayer for PNG today is; “Yahweh, I know you are near. Standing always at my side. You guard me from the foe and you lead me, in ways everlasting…”

Next week: The Physical processes in science and technology

Michael Uglo is the author of the science textboook Science in PNG, Pacific, Asia and Caribbean” and a lecturer in Avionics, Auto- Piloting and Aircraft Engineering)
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