Modern Periodic Law
How many Gaseous Elements are there in Periodic Table
Which is the most reactive nonmetal?
Define representative elements?
What does the group number mean on the periodic table of elements?
F < Cl < Br < I is the correct arrangement in terms of :
The atom of an element has 20 protons, 20 electrons, and 20 neutrons :
(a) What is the atomic number of the element?
(b) What is the mass number of the element?
(c) Name the element.
(d) Write the electronic configuration of the element.
Write down the chemical formula of Zinc.
In modern periodic table nitrogen is placed just before oxygen in the 2nd period because:
The given statement is false. In the modern periodic table oxygen is placed before nitrogen.
Oxygen has one more proton in its nucleus than nitrogen.
Nitrogen has bigger atomic radius than oxygen.
Oxygen is more electronegative than nitrogen.
The electronic configuration of an element is 2, 8, 7:
- What is the group number of T?
- What is the period number of T?
- What is the valency of T?
- Is T a metal or non-metal?
- How many valence electrons are there in the atom of T?
Which of the following elements is used to make pencil lead?
Why is CuSO4 the expected formula of Copper Sulphate and not Cu2SO4 when Copper has variable valency of Cu+ and Cu2+ ; Here the higher valency is used for the salt.
However in the case of Iron Sulphate the expected formula is FeSO4 and not Fe2(SO4)3 eventhough Iron also has variable valency of Fe2+ and Fe3+ ; Here the lesser valency is used for the salt.
In the modern periodic table, the elements are arranged on the basis of their increasing atomic number.
Name the longest period in the modern periodic table.
Phosphorus is a metal or nonmetal?
Why are elements belonging to group 18 called noble gas elements?
What are typical or representative elements in the modern periodic table?
Define the modern periodic law. Why was it necessary to change the basis of classification?
The formula of ion formed by an element A is . The element A can probably belong to which of the following groups?
An element combines with oxygen to form an oxide which is good conductor of electricity. Give the following information:
- How many electron will be present in the valence shell of element ?
- Write the formula of the compound formed when the element combines with chlorine.
What is the periodic table of Elements?
How to find neutron?
A recently discovered isotope of the noble element oganesson (symbol ‘Og’) has electronic configuration 2, 8, 18, 32, 32, 18, 8 and mass number 294.Calculate the number of electrons, protons and neutrons in its atom.
The atomic particle whose number in the atoms of an element always remains the same and which forms the real basis for the modern classification of elements is :
(a) electron (b) proton (c) neutron (d) meson