Test: Periodic Classification of Elements - SSC CGL MCQ

Mendeleev's periodic law was based on atomic masses, whereas the modern periodic law, proposed by Moseley, is based on atomic numbers. Moseley's discovery emphasized that the properties of elements are better understood in relation to their atomic numbers rather than atomic masses.

Elements are classified in the periodic table based on their electronic configuration by the number of outermost shells. This classification helps in organizing elements according to their properties and relationships with other elements.

The p-Block elements in the periodic table include a variety of elements such as metals, non-metals, and metalloids. This block spans groups 13 to 18 and exhibits diverse properties depending on the element's position within the block.

The correct option is C
ns⁰⁻² (n−1)d¹⁻¹⁰
(n-1)d has to be filled and the ns orbital may or may not be filled.
(n-1)d orbital has a lower energy than the ns orbital.

Ununseptium, a new super heavy element, belongs to group 17 in the periodic table. This element was created and observed by researchers at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany.

Electronegativity is the periodic property that describes an atom's ability to attract a shared pair of electrons towards itself. This property increases along a period and decreases down a group. It is an essential concept in understanding chemical bonding and the behavior of elements in compounds.

Metallic character decreases along a period in the periodic table. This means that elements become less metallic in nature as you move from left to right across a period. Metallic character is related to an element's tendency to form cations by losing electrons.

The valency of elements with respect to hydrogen increases from 1 to 7 across a period. Valency is the combining power of an element, indicating the number of hydrogen atoms with which one atom of an element can combine.

The basic nature of oxides increases along a group in the periodic table. This means that as you move down a group, the oxides of elements exhibit more basic properties. Basic oxides typically react with acids to form salts and water.

The reducing character of elements decreases along a period in the periodic table. This means that elements have a lower tendency to act as reducing agents (to donate electrons) as you move from left to right across a period.

Hydrogen is the most abundant element in the universe by mass, making up approximately 70% of the total mass of the universe. This abundance of hydrogen is due to its presence in stars, including our sun, and its fundamental role in the composition of living organisms as well.

Hard water does not form lather with soap due to the presence of calcium or magnesium compounds, which cause the hardness. This characteristic of hard water is a result of the minerals it contains and can have implications for various household and industrial applications.

Tritium is a rare and radioactive isotope of hydrogen with a mass number of 3 and an atomic number of 1. It has a relatively short half-life of 12.4 years and is used in various applications, including as a tracer in scientific research.

Nascent hydrogen is more reactive than molecular hydrogen and appears suddenly during a chemical reaction. This form of hydrogen exhibits enhanced reactivity due to its freshly formed state, making it important in various chemical processes and industrial applications.

Heavy water is a colorless, odorless, and tasteless liquid with a higher density than ordinary water, attributed to the presence of deuterium. It has unique physical properties and is utilized in various scientific and industrial applications due to its isotopic composition.