Structure of the Atom | HL IB Physics Topic Questions 2025

1

1 mark

Which of the following statements about the nuclear radius is incorrect?

As more nucleons are added to a nucleus the radius increases
The radius of nuclei depends on the atomic number, Z of the nucleus
The exact relationship between the radius and nucleon number can be determined from experimental data
The radius of the nucleus can be calculated using an equation which involves the constant of proportionality, R₀

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1

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In 1890 Johannes Rydberg discovered an empirical formula that enabled the wavelengths of the light in the atomic line spectrum of hydrogen to be calculated. The formula is:

$\frac{1}{λ} = R_{H} (\frac{1}{n^{2}} - \frac{1}{m^{2}})$

Where λ is the wavelength, n and m are integers and R_H is the Rydberg constant.

In 1913 Niels Bohr published his theory of the hydrogen atom. This theory enabled the Rydberg formula to be derived. His theory also showed that the energy levels E_n of the hydrogen atom are given by the formula:

$E_{n} = \frac{2.2 \times 10^{- 18}}{n^{2}}$

Where E_n is measured in joules.

Which of the following is a valid expression for the Rydberg constant?

$R_{H} = 2.2 \times 10^{- 18}$
$R_{H} = \frac{2.2 \times 10^{- 18}}{h c (1 - \frac{n^{2}}{m^{2}})}$
$R_{H} = \frac{2.2 \times 10^{- 18}}{h c}$
$R_{H} = 2.2 \times 10^{- 18} (\frac{n^{2} - m^{2}}{m^{2} - n^{2}})$

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1 mark

According to the Bohr model for hydrogen, visible light is emitted when electrons make transitions from excited states down to the state with n = 2.

The dotted line in the diagram represents such a transition, from n = 3 to n = 2, in the spectrum of hydrogen.

12-1-hl-mcq-medium-q10-diagram

Which of the following diagrams could represent the visible light emission spectrum of hydrogen?

12-1-hl-mcq-medium-q10-real_options

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	Atomic number	Speed
A.	decrease	increase
B.	decrease	decrease
C.	increase	increase
D.	increase	decrease

	E / MeV	Z
A.	39.0	350
B.	2.4	190
C.	39.0	190
D.	2.5	350

	Frequency	Wavelength
A.	$f_{3} = f_{1} + f_{2}$	$\frac{1}{λ_{1}} = \frac{1}{λ_{2}} + \frac{1}{λ_{3}}$
B.	$f_{3} = f_{1} - f_{2}$	$\frac{1}{λ_{1}} = \frac{1}{λ_{2}} + \frac{1}{λ_{3}}$
C.	$\frac{1}{f_{1}} = \frac{1}{f_{2}} - \frac{1}{f_{3}}$	$λ_{1} = λ_{2} + λ_{3}$
D.	$\frac{1}{f_{1}} = \frac{1}{f_{2}} + \frac{1}{f_{3}}$	$\frac{1}{λ_{3}} = \frac{1}{λ_{1}} - \frac{1}{λ_{2}}$

	I.	II.
A.	most α-particles miss the gold atoms	a small number of α-particles are deflected by the gold atoms
B.	the nucleus of the gold atom is very small so that most α-particles do not interact with it	the ratio of deflected particles is small because it reflects the ratio of the size of the nucleus compared to the atom
C.	the charge on the nucleus is insufficient to deflect the α-particle	the ratio of deflected particles is small because it reflects the ratio of the size of the nucleus compared to the atom
D.	α-particles are high energy and able to pass through the nucleus	the charges on the α-particle and the nucleus are such that large angle deflection cannot occur

Structure of the Atom (HL IB Physics)

Topic Questions