According to IUPAC recommondations, the number of groups in the long form of the periodic table is :-
How many elements did Mendeleev classify?
How many elements are placed in lanthanide and actinide series?
The same holds for the actinide series that runs from atomic number 90 through to number 103, again 14 elements. Thus, as you move from thorium (Th) at element number 90, you begin to fill up the 5f sublevel and continue to fill up the 5f sublevel until you finish the actinide series at lawrencium (Lr).
Which of the following elements of noble gases participate in chemical reaction?
Kr and Rn are the noble gases which participate in the chemical reactions.
In the modern periodic table which are the metals among the first 10 elements?
Nitrogen and phosphorus belong to the group 15 of the periodic table. Which of these will be more electronegative?
Nitrogen is smaller in size as compared to Phosphorus. Due to its small size, the net electron charge increases. Hence, its nucleus exerts greater force on the electrons. That is the reason why, Nitrogen is more electronegative element than Phosphorus.
Modern Periodic law is based upon-
The second ionization energy is greater than the first because
The atomic number of an element is 16 predict the nature of the element
When metals react with non-metals, electrons are transferred from the metal atoms to the non-metal atoms, forming ions. The resulting compound is called_____
Give the symbol for the most reactive non-metal of group 17
Which one has the bigger size?
Potassium atoms have 19 electrons and 19 protons with one valence electron in the outer shell.It has more no. of shells as compared to the other elements.
Which set of elements is listed in order of increasing ionization energy?
Which of the following element forms dipositive ion very easily?
Which of the following is not the limitation of Mendeleev’s periodic table?
What is the atomic number of the first element of the lanthanide series?
Statement A : Electron affinity of fluorine is more than that of chlorine.
Statement B : Carbon monoxide is an acidic oxide.
Carbon monoxide is usually treated as if it was a neutral oxide, but in fact it is very, very slightly acidic.E.A of fluorine is less than that of chlorine.
Statement A : energy is always released when a neutral atoms gain an electron
Statement B Tellurium and polonium are semi metals
Metalloids are chemical elements that display properties of both metals and nonmetals. Usually, the semimetals or metalloids are listed as boron, silicon, germanium, arsenic, antimony, tellurium, and polonium.
What is the number of valance electrons in the last element of 3rd period?
Arrange the following elements in the decreasing order of their atomic radii
Metallic character ____________ down a group
Elements having same valence electrons are placed in same group but there is an exception with-
P, Q, R are elements of Dobereiner’s triads. If the atomic mass of P is 7 and that of Q is 23, What will be the atomic mass of R?
(P+R)/2 = Q....(7+R)/2 = 23......7+R = 23×2.........R = 46 - 7 ........R = 39.0.
Which element was discovered after Mendeleev gave the periodic table?
An element with atomic no 3 combines with another elements with atomic number 17, What would be the formulae of the compound?