Category Chemistry

               You must have seen the launching of rockets on television. Rockets shoot up straight into the sky, and disappear among the clouds in no time. They are so fast. The element used for the propulsion of rockets is hydrogen.

               Hydrogen is the most abundant element in the universe. And it is a highly flammable element. When hydrogen comes in contact with oxygen, it produces violent reactions. The explosion generates sufficient energy to propel the rocket upward and break the gravitational pull of the Earth. Besides, the reaction produces an almost invisible flame too.

               Hydrogen is a colourless gas. And it is the only element which lacks any neutrons. Let us look at some other characteristics that make this element special!

               Hydrogen is the lightest of all elements. It is even lighter than air; and therefore, in its pure form it will easily escape from Earth’s gravity into space. Hence, hydrogen present on earth exists in chemical compounds such as water. When extreme pressure is applied to it, hydrogen turns into liquid form. Its atomic number is one and the symbol is H.

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               The periodic table as we know it today is not a work of a single individual. Many brilliant men have devoted their time and energy to its design and completion.

               In 1789, Antoine Lavoisier, a French chemist, published a table with 33 elements known at that time. However, the breakthrough came when two distinguished scientists, Dmitri Mendeleev, a Russian chemistry professor, and Julius Lothar Meyer, a German chemist, independently published their periodic tables in 1869 and 1870 respectively. Mendeleev’s periodic table gained more popularity than Meyer’s, and gradually, his table was recognized and widely used by the scientific community world over.

               Mendeleev’s achievement has an interesting anecdote associated with it. It is said that the idea of periodic table occurred to him in a dream! He was dreaming about a card game of Patience. Horace Groves Deming is credited for the popular layout of the periodic table we have today.

               The periodic table lists and arranges elements in the order of their atomic number. There are rows and columns in it. The vertical column in the table is known as a group, while the horizontal row is called a period. These groups are assigned numbers, and some of these groups have accepted names. For example, elements of group 17 are known as halogens; and number 18 is the group of noble gases.

               Philosophers in ancient times believed that everything in the universe was composed of extremely small and indivisible units called atoms. But their idea of an atom differed from what modern scientists understand of it today. In fact, elements, the basic building blocks of matter, are composed of tiny particles called atoms.

               And what are atoms made up of, in turn? Every atom has a nucleus. It is made up of protons and neutrons and is surrounded by the electron cloud.

               Protons possess positive electrical charge and electrons carry negative electrical charge. Neutrons have no electrical charge at all. An atom is usually neutral, as the number of protons and electrons in it is equal. John Dalton, a renowned English scientist, is known for introducing atomic theory into chemistry.

               Atoms of the same element are identical. For example, all atoms in oxygen are the same. Atoms of one element can combine with atoms of another element to form new substances. Such new substances are known as chemical compounds. A compound is atoms from diverse elements combined together. Water, sugar and salt are examples.

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               Every part of the human body is made up of elements at the most basic level. So is the case with everything else in the universe.

               If we observe the construction of a building, we will see the builder placing one brick over another to raise a wall. Elements to things are like bricks to a building. They are the fundamental building blocks of matter. We know of 118 kinds of elements today.

             What makes one kind of element different from another is the number of protons in its atomic nucleus. Hydrogen has only one proton in its nucleus; whereas, oxygen has 8. These numbers are known as the atomic numbers of these elements.

               An element is known by its atomic number and a symbol. The symbol is often an abbreviation of the Latin name of the element. While the symbol of hydrogen is H, the symbol of iron is ‘Fe’. This is because iron is ‘ferrum’ in Latin. Of the 118 elements that we know today, not all elements occur naturally on Earth. Ninety-four of them are natural, while many others can be created artificially.

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