Test: Periodic Trends in Properties of Elements - NEET MCQ

When we go down in a group shell increase and size increase and due to large size of atom electron can easily be removed. Thats option is C.

Isoelectronic are the species having same number of electrons.
A positive charge means the shortage of an electron.

The cause of periodicity of properties of elements is due to the repetition of similar electronic configuration of their atoms in the outermost energy shell after certain regular interval.

The tendency of an atom in a molecule to attract the shared pair of electrons towards itself is called its electronegativity.
Electronegativity is a dimensionless property since it is only a tendency. It only indicates the net result of the tendencies of different elements to attract the bond forming electron pair.

Al³⁺ because they all have the same number of electrons, however Al3+ has the most protons and therefore greatest nuclear charge. In Al³⁺, the same number of electrons are being attracted by more protons in the nucleus, so the electrons are being pulled closer to the nucleus, reducing the size of the ionic radius.

According to the electronic configuration of sodium(Na),it has 1 valence electron(2,8,1).So it loses one electron to form a cation and becomes sodium cation (Na+).As it loses one electron ,the outermost shell has 0 electrons (i.e it gets eliminated ) and Na+ has only 2 shells. Hence, it lost one of its shell, the sodium ion is smaller than the sodium atom.

The negative electron gain enthalpy of fluorine is less than that of chlorine. It is due to small size of fluorine atom. As a result, there are strong interelectronic repulsions in the relatively small 2p orbitals of fluorine and thus, the incoming electron does not experience much attraction.

Carbon has the highest first ionisation energy because ionisation energy decreases down the group and increases from left to right in a period.

Strontium has the highest atomic radii because it on the group atomic radius increases also it belongs to 4D so if there is doubt of Lanthanide contraction then the size of 4D is largest followed by 3D and 5D has the smallest size.

It is believed that Noble gases don't form (or rather don't easily form bonds). This way only Van der Waals radius is measured.

The rationale here is based on the fact that noble gases have very low chemical reactivity and their atomic radii are non bonded.

Si,P,C,N

Electronegativity increases along a period and decreases down the group.Nitrogen is expected to have maximum electronegativity.

The option (d) represents incorrect statement. It states that 
"Removal of electron from orbitals bearing lower n value is easier than from orbital having higher n value".
The correct statement is "Removal of electron from orbitals bearing lower n value is difficult than from orbital having higher n value".
The attraction between the nucleus and the electron present in orbital having lower n value is higher than the attraction between the nucleus and the electron present in orbital having higher n value.

Ionisation energy increases along a period. The very next elements C,N,O,F results F with higher ionisation energy.

The mole concept, which we will introduce here, bridges that gap by relating the mass of a single atom or molecule in amu to the mass of a collection of a large number of such molecules in grams. As you learned, the mass number is the sum of the numbers of protons and neutrons present in the nucleus of an atom.

Atomic radius is generally decreases from left to right along a period because the electrons are added to same shell due to this they experience a great force from the nucleus. While atomic radiusincreases in group from top to bottom cause new shells are added and the electrons are bring away from the nucleus.

Electron affinity is defined as the change in energy (in kJ/mole) of a neutral atom (in the gaseous phase) when an electron is added to the atom to form a negative ion.

F^- is isoelectronic with Ne  both have 10 electrons

Among the given molecules, N₂ has highest ionization enthalpy.The reason behind is the stability of half-filled orbitals which makes it more stable than other elements in the given option list.

Atomic radius decreases along period, the very next elements K ,Ca has K has higher atomic radius.

Electron gain enthalpy values of noble gases are positive because they have stable electronic configuration and thus have no tendency to take additionalelectron.