The question asks about the number of periods and groups in the modern periodic table. This is a fundamental concept in chemistry, and the structure of the periodic table is standardized globally. We need to recall the definitions of periods and groups and their respective counts.
A) 7 Periods and 18 Groups — This option correctly states the number of periods (horizontal rows) and groups (vertical columns) in the modern periodic table.
The question asks to identify the correct statements about non-metals from the given options. We need to evaluate each statement based on the general properties of non-metals.
Based on the evaluation, statements (i) and (iii) are correct.
Correct Option: B) (i) and (iii) only
The question asks for the definition of an 'ore' in the context of mineral extraction. An ore is not just any mineral from which a metal can be obtained, but specifically one from which it can be extracted economically and practically.
Correct Option: A) Can be extracted from it profitably
The question asks about the total number of known elements and how many of them occur naturally. This is a factual question based on current scientific understanding of the periodic table.
Correct Option: B) 118,94
The question asks about the applicability of Newlands' Law of Octaves. This law stated that when elements are arranged in increasing order of atomic masses, the properties of every eighth element are similar to the first. However, this law had limitations and was only applicable to lighter elements.
A) Calcium — Newlands' Law of Octaves was applicable only up to Calcium. After Calcium, the properties of elements did not follow the octave pattern.
The question asks for the term used to describe the earthy impurities associated with minerals in metallurgy. Understanding the basic terminology used in the extraction of metals is crucial here.
B) Gangue — Gangue refers to the unwanted, earthy, or rocky impurities that are present along with the valuable mineral in an ore. These impurities must be separated from the mineral during the beneficiation and extraction processes.