1) In Mendeleev’s periodic table, there are 8 groups and each group is divided into two sub-groups designated as A and B. Mendeleev arranged the elements according to their atomic weights. ... So he divided the group into two subgroups containing elements having same physical and chemical properties and named them A and B.
What is the difference between group A and group B elements?
In group A elements, the added electrons goes to the outermost shell. In group B, the additional electron goes to penultimate shell . For example, in group III A, the added or increased electron occupies outermost shell. ... The number of valence electrons increases.
What does A and B mean on the periodic table?
Elements are arranged by reactivity in the periodic table. Elements with similar reactivity are put into the same column or group. ... The columns with B (IB through VIIIB) are called the transition elements . The columns with A (IA through VIIIA) are called the main group elements.
What are A and B subgroups in periodic table?
Elements of A and B subgroups: Except for the formal similarity in the composition of the compounds of elements of A and B subgroups, there is almost no resemblance in their nature or In groups IV, V, VI and VII, the subgroup A contains electronegative elements, whereas the subgroup B contains metallic elements .
What are subgroups in Mendeleev periodic table?
In Mendeleev’s periodic table, the groups were divided into two subgroups. Groups from I to VII are meant for normal elements and group VIII is for transition elements . Groups from I to VII have been divided into two subgroups, while group VIII is meant for three elements.
What are periods in a periodic table?
In chemical bonding: Arrangement of the elements. The horizontal rows of the periodic table are called periods. Each period corresponds to the successive occupation of the orbitals in a valence shell of the atom , with the long periods corresponding to the occupation of the orbitals of a d subshell.
What are 3 family names of the periodic table?
Families on the periodic table include, in addition to noble gases and halogens, the alkali metals, alkaline earth metals, transition metals, lanthanides, and actinides .
Are groups vertical or horizontal?
A group is a vertical row of the periodic table.
What is Group 1 on the periodic table called?
Group 1A (or IA) of the periodic table are the alkali metals : hydrogen (H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). ... The alkali metals have only one valence electron in their highest-energy orbitals (ns 1 ).
What is group 5 on the periodic table called?
Group 5A (or VA) of the periodic table are the pnictogens : the nonmetals nitrogen (N), and phosphorus (P), the metalloids arsenic (As) and antimony (Sb), and the metal bismuth (Bi).
What is Group 13 on the periodic table called?
Boron group element , any of the six chemical elements constituting Group 13 (IIIa) of the periodic table. The elements are boron (B), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), and nihonium (Nh).
Which is Eka Aluminium?
Eka-aluminium was the name given by Mendeleev to the undiscovered element which now exists by the name of Gallium . Gallium belongs to group 13 of the periodic table. Its atomic number is 31 with the symbol Ga . It is a soft, silvery metal at standard temperature and pressure.
What is Group 17 on the periodic table called?
Halogen , any of the six nonmetallic elements that constitute Group 17 (Group VIIa) of the periodic table. The halogen elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts).
What are the rows of Mendeleev periodic table called?
Mendeleev created a periodic table of all the elements that were known at the time. The rows of the table, called periods , each contained eight elements that increased in atomic mass from left to right. The columns of the table, called groups, contained elements with similar properties.
How many groups are in Mendeleev periodic table?
-There are a total of 8 groups and 7 periods in the modified Mendeleev table. -There are a total of 18 groups and 7 periods in the modern periodic table that is followed worldwide now.
What does Mendeleev’s periodic law state?
the law that the properties of the elements are periodic functions of their atomic numbers . Also called Mendeleev’s law. (originally) the statement that the chemical and physical properties of the elements recur periodically when the elements are arranged in the order of their atomic weights.
