Besides gallium, which other elements have since been discovered that were left by Mendeleev's in his Periodic Table ? (any two)

What were the criteria used by Mendeleev in creating his Periodic Table ?

What property did Mendeleev use to classify elements in his periodic table?

(i) Newlands proposed the law of octaves. ii) The law of octaves was not valid for elements that had atomic masses higher than calcium. iii) Newlands left blanks for new elements in his periodic table. Which statement is wrong?

Which element is placed in two different groups of the long form of the periodic table?

Who was left the blanks in his periodic table for some undiscover elements ?

PASSAGE - 1: In Mendeleeff's periodic table elements were classified on the basis of atomic weight & in modern periodic table on the atomic number. The lighter elements of 2 & 3 periods show similarities in their properties called diagonal relationship 1. Which of the following element is not present in Mendeleeff's periodic table

PASSAGE - 1: In Mendeleeff's periodic table elements were classified on the basis of atomic weight & in modern periodic table on the atomic number. The lighter elements of 2 & 3 periods show similarities in their properties called diagonal relationship Due to digonal relation which pair are amphoteric in nature

Numerous forms of the periodic table have been devised from time to time. A modern version which is most convenient and widely used is the long or extended from of periodic table. The aufbau principle and the electronic configuration of atoms provide a theoretical foundation for the periodic classification. The horizontal rows are called periods. There are altogether seven periods. The first period consists of 2 elements. The subsequent periods consists of 8, 8,18, 18 and 32 elements respectively. The seventh period is incomplete and like the sixth period would have maximum of 32 elements. Elements having similar outer electronic configurations in their atoms are grouped in vertical columns. These are referred to as groups or families. According to the recommendations of IUPAC, the groups are numbered 1 to 18 replacing the older notation of groups 0, IA, IIA, ....VIIA, VIII, IB.....VIIB. Each successive period in the periodic table is associated with the filling up next higher principal energy level following aufbau sequence. The number of elements in each period is twice the number of atomic orbitals available in the energy level that is being filled. All the elements are classified into four blocks, i.e., s-block, p-block, d-block, and f-block depending on the type of atomic orbitals that are being filled with electrons. What is the position of the element in the periodic table satisfying the electronic configuration (n-1)d^1 ns^2 for n=4 ?

Which period starts with M main shell? Name the sub-shells in it? How many elements are there in this period ? Name any two elements in it ?

In the modern periodic table, the elements are placed in order to increasing atomic number. These have been numerous designs of the table over the years but the most common is the long form of periodic table. The long form of periodic table shows all the elements in numerical order. Write the expected ground state electronic configuration of the element with one unpaired 5p electron that forms a covalent compound with fluorine.