Long-form of Periodic Table

Long-form of Periodic Table

The modern periodic table of elements is a grid that groups elements into families that are related to one another in chemical properties. Its fundamental building block is the period. A period is a row of elements with the same number of electrons in their outer shell. For example, the period of the alkali metals (column 1) contains two hydrogen-like elements. The second row is helium-like and consists of two helium-like elements; the third row has eight inert gases, the fourth one carbon and nitrogen, the fifth one silicon and sulphur, and so on.

The modern table arranges all the known elements, except for recently discovered ones, in order of increasing atomic number. The order of a particular element within a column can be determined by its position in the periodic table: each element has a unique set of properties and its position in the table is determined by its electron configuration or arrangement within atoms. For example, all noble gases have full shells so they are placed in Group 8 (the noble gases). In some cases, however, it is impossible to predict whether an element will fit into a full or half-full shell; this happens when an element has similar properties to two different elements (for example gallium has properties similar to both aluminium and thallium).

The original periodic table was devised by Russian chemist Dmitri Mendeleev. Mendeleev arranged the known chemical elements in his table so that those with similar properties were grouped together, making it easier to study them. It was first published in 1869 and has since been refined to show more accurate relationships between elements and their properties.

Groups

A group is a small vertical column in the modern or long form of the periodic table. The horizontal rows are periods. The columns are called groups. Hydrogen is in group 1; helium is in group 2.

The elements in a group have similar properties. They tend to react with one another in similar ways. For example, they usually form colored compounds (sodium forms yellowish-orange compounds with chlorine, sulfur forms yellowish-brown compounds with chlorine).

The periodic table is a unique representation of chemical elements. It does not give us any information about the state of matter, physical or chemical properties, atomic mass, or atomic weight.

The periodic table is a chart of the elements arranged according to their atomic number and electronic configuration. The electronic configurations are derived from the electron configurations of the neutral atoms, which are shown in the leftmost column. The periodic table is an arrangement of the elements according to their electron configurations.

All elements have one electron outside their nucleus. All these electrons make up a cloud around the nucleus, called an electronic configuration. The first row in the periodic table shows all these electrons to be in a single shell (called K-shell). The second row shows that two electrons are added to a new shell i.e., L-shell. The third row shows that three electrons are added to a new shell i.e., M-shell.

The elements in any given group have their outer electrons in the same orbital. But they differ in the number of electrons (or electron pairs) in that orbital, and in the energy of their outermost shell; these differences determine how easily the elements react with one another.

For instance, we say that gold and mercury are both metals, but gold is a much more reactive metal than mercury. This means that it takes much more effort to make gold and mercury react with one another than to make gold and silver react with one another.

Periods

Periods are not to be confused with groups. A periodic table may be depicted in a number of ways, and the two are most commonly confused because they both depict columns of elements. The modern or long form of the periodic table arranges the elements in order of increasing atomic number within each period.

Periods, on the other hand, are numbered from 1 through 7 starting at the top left (hydrogen) and proceeding across until reaching the last period which is diagonal to the right at the bottom (noble gases). Periodicity is a property of a single element; period is a property of an entire group of elements. For example, caesium, with an atomic number (abbreviated Z) of 55, has period 7 in group 1.

The second period contains the elements lithium, beryllium, and boron. Lithium and beryllium are in period 2 as they have two electrons in their outer orbit or shell. Boron is special because it has three electrons in its outer shell but still belongs to period 2 instead of period 3.

The third period consists of 12 elements from carbon (C) through to neon (Ne). Elements belonging to this period have four electrons in their outer shell – so the total number of electrons for all atoms belonging to period 3 is 8.

The fourth period consists of 14 elements – sulphur (S) through to argon (Ar). These are known as halogens because they form compounds readily with non-metals. The total number of electrons for all atoms belonging to this period is 10.

The fifth period consists of 8 elements from potassium (K) through to radium (Ra). The total number of electrons for these atoms is 18 – 2 more than the ‘usual’ number of 16. The sixth period only has two elements – actinium and thorium. The total number of electrons for both these elements is 20. Lastly, the seventh period has 8 elements that include protactinium, and uranium.

The lanthanide consists of 39 elements. They go by a variety of different names. Some of them have more than one name. Lutetium and gadolinium have three names each. That’s because they were first discovered in separate places, and each place wanted to name them after itself. The actinides consist of 15 elements. The last two in this group are actually considered to be radioactive, although they don’t give off as much radiation as some other radioactive substances do.

Conclusion

In this material, we discussed the concept of the Long Form of the periodic table. Along with that, we also discussed how the groups and periods are classified in the modern form of the periodic table.