Moseley's Law

Q. In 1913, Moseley discovered the relationship between the X-ray spectra frequency and the atomic number of elements. If we draw a curve between the X-ray frequency $\left(\sqrt{\nu }\right)$ and the atomic number $\left(Z\right)$, it will be a:

1. Parabola
2. Hyperbola
3. Straight line
4. Rectangular Hyperbola

Q. The basis of long form of periodic table is

1. atomic mass
2. atomic number
3. mass number
4. size of the atom

Q.

Are there any trick's to write mass number of elements from 1to 30

Q.

In what manner is the long form of periodic table better than Mendeleev's periodic table? Explain with examples.

Q. In 1913, Moseley, a young physicist, discovered the relationship between the X-ray spectra frequency and the atomic number of elements. If we draw a curve between the X-ray frequency $\left(\sqrt{\nu }\right)$ and the atomic number $\left(Z\right)$, it will be a:

1. Parabola
2. Hyperbola
3. Straight line
4. Rectangular Hyperbola

Q. Calculate the number of formula units of $FeS{O}_4\cdot 7H_{2}O$ in $0.5\text{millimoles}$ of pure $FeS{O}_4\cdot 7H_{2}O$.

1. $0.5N_A$
2. $0.005N_A$
3. $0.0005N_A$
4. $5000N_A$

Q.

What is the basis of the modern periodic table?

Q. How are $0.50\text{mol}N{a}_{2}C{O}_3\text{and}0.50MN{a}_{2}C{O}_3$ different?

Q.

According to Moseley, a straight line graph is obtained on plotting

1. The frequencies of characteristic X-rays of the elements against their atomic numbers.

2. The square of the frequencies of the characteristic X-rays of elements against their atomic numbers

3. The square root of the frequencies of the characteristic X-rays of elements against their atomic numbers.

4. The reciprocal of the frequencies or characteristic X-rays of elements against their atomic numbers.

Q. A photon of wavelength 4*10^-7 strikes on metal surface ; the work function of the metal being 2.13ev . Calculate (1) the energy of the photon , (ii) the kinetic energy of the emission (iii) the velocity of the photoelectron.

Q. The horizontal rows in a periodic table are called group.

1. True
2. False

Q.

1. True
2. False

Q. In 1913, Moseley, a young physicist, discovered the relationship between the X-ray spectra frequency and the atomic number of elements. If we draw a curve between the X-ray frequency $\left(\sqrt{\nu }\right)$ and the atomic number $\left(Z\right)$, it will be a:

1. Parabola
2. Hyperbola
3. Straight line
4. Rectangular Hyperbola

Q. The basis of long form of periodic table is

1. atomic mass
2. atomic number
3. mass number
4. size of the atom

Q.

What is the basis of long form of periodic table?

1. Atomic mass

2. Atomic number

3. Atomic size

4. Metallic & non-metallic character

Q. Define the Modern Periodic law. Why was it necessary to change the basis of classification from the atomic mass to the atomic number?

Q.

The statement that is not correct for the periodic classification of elements is

1. The properties of elements are the periodic functions of their atomic numbers

2. Non-metallic elements are lesser in number than metallic elements

3. The first ionization energies along a period do not vary in a regular manner with increase in atomic number

4. For transition elements, the sub-shells are filled with electrons monotonically with increase in atomic number

Q. Total number of inner transition elements are :

Q.

How are elements arranged in the modern periodic table?

Q.

What is the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from an energy level with n = 4 to an energy level with n = 2?

Q. Eka-aluminium and eka-silicon are known as__________.

1. Iron and Sulphur
2. Proton and Silicon
3. Gallium and Germanium
4. Aluminium and Silicon

Q. Compare Mendeleev and modern periodic tables
i) on the basis of groups.
ii) on the basis of properties of elements.
iii) on the basis of classification.

Q. Monochromatic radiation of specific wavelength is incident on H-atoms in the ground state. H-atoms absorb energy and emit subsequently radiations of six different wavelengths. Find the wavelength of incident radiations:

1. $97.25nm$
2. $9.75nm$
3. $50nm$
4. $85.8nm$

Q.

Electromagnetic radiation of wavelength 242 nm is just sufficient to ionise the sodium atom. Calculate the ionisation energy of sodium in kJ mol^–1.

Q. Which of the following statements are correct about noble gases?

1. They are in between halogens and IA group.
2. These elements belong to ${17}^{th}$ group in IUPAC system.
3. These are highly reactive elements.
4. Except $Rn$, all the remaining atoms are present in the air.

Q. The energy difference and the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from the energy level n = 4 to the energy level n =3, given that value of Rydberg constant is 1.0974 $\times$ 10${}^{-7}$ m${}^{-1}$ will be:

1. $\Delta$E=2.12 $\times {10}^{-19}$ , $\lambda$=1.875 $\times$ 10${}^{-12}$ m
2. $\Delta$E=1.06 $\times {10}^{-19}$ , $\lambda$=1.875 $\times$ 10${}^{-12}$ m
3. $\Delta$E=2.12 $\times {10}^{-19}$ , $\lambda$=1.875 $\times$ 10${}^{-6}$ m
4. $\Delta$E=1.06 $\times {10}^{-19}$ , $\lambda$=1.875 $\times$ 10${}^{-6}$ m

Q. Ionisation potential values of noble gases decrease down the group with increase in atomic size. Xenon forms binary fluorides by the direct reaction of elements. Identify the correct statement(s) from below.

1. It happens because the compounds are formed with electronegative ligands
2. Octet of electrons provide the stable arrangements
3. It happens because the noble gases have higher ionisation energies
4. Only the heavier noble gases form such compounds

Q.

Which of these following will be in increasing order in the modern periodic table?

1. No of neutrons

2. Atomic number

3. Atomic mass

4. All of these

Q. Modern periodic table is based on:

1. atomic weight
2. atomic size
3. atomic volume
4. recurrence of chemical properties

Q. Determine the molecular formula of an oxide of iron, in which the mass percent of iron $\&$ oxygen are $69.9\&30.1$ respectively.