Last seen: Sep 10, 2021
1. Group 17 represents the halogen family. All the elements included in the family are non-metals. Therefore, element A is a non-metal. 2. Reactivit...
(a) The atomic number of the element is 17 (2 + 8 + 7 = 17). (b) It would be chemically similar to fluorine (F) which has also 7 electrons in its va...
(a) All elements in the same column of the Periodic Table as that boron belong to Group 13 and thus have three valence electrons. (b) All these elem...
(a) The elements with completely filled shells are noble gas elements and they belong to group 18. Since the element has two shells, it must be presen...
(c) The atoms lose their electrons more easily.
Before identifying the metallic character from the list of the elements, we must remember two points: The metallic character of an element is rela...
Metals among the first ten elements are lithium (Li) and beryllium (Be). These are placed towards the left of the table.
(a) The atoms of all these elements have one electron each in their valence shell. That is why, these elements are placed in the group 1 known as alka...
(i) Lithium, sodium, potassium (alkali metals) (ii) Beryllium, magnesium, calcium (alkaline earth metals) (iii) Helium, neon, argon (noble gases).
Magnesium (Mg) belongs to group 2 known as Alkaline Earth Family. The two other elements belonging to the same group are calcium (Ca) and strontium (S...
Modern Periodic Table or Long Form of Periodic Table: In the Modern Periodic Table, the elements are arranged in increasing order of their atomic n...
In Mendeleev’s Periodic Table, the elements have been arranged in different groups on the basis of valency. For example, the elements placed in group ...
Mendeleev used atomic masses of the elements as the criteria for creating his periodic table. In this table, the elements were arranged in order of in...
Two other elements are scandium (Sc) and germanium (Ge). In their gaps, the elements with names Eka-boron and Eka-silicon were placed.
Oxygen is a member of group VIA in Mendeleev’s periodic table. Its valency is 2. Similarly, the valencies of all the elements listed can be predicted ...
Limitations of Newlands’ Law of Octaves The law of octaves was found to be applicable only up to calcium. It was not applicable to elements of hig...
Limitations of Dobereiner’s Triad All known elements could not be classified into groups of triads on the basis of their properties. Not all grou...
Yes, some of the Doberiener’s triads did exist in the columns of Newlands’ Octaves. For example, Li, Na, K (triad) Be, Mg, Ca (triad)
Cleansing Action of Soap: Soaps contain two chemically distinct parts: a long hydrocarbon tail and the other negatively charged head. The long hydro...