2.1 - The Nuclear Atom

The atom of an element Q has an atomic number of 27 and a mass number of 60. Which of the following statements is true about the subatomic particles of the atom of element Q?

• I.$\hspace{1em}$	Atom of element Q has 27 electrons and 60 protons
  II.$\hspace{1em}$	Atom of element Q has 27 protons and 27 electrons
  III.$\hspace{1em}$	Atom of element Q has 27 electrons and 60 neutrons
  IV.$\hspace{1em}$	Atom of element Q has 27 protons and 33 neutrons

• A.$\hspace{1em}$ I and IV only

• B.$\hspace{1em}$II and IV only

• C.$\hspace{1em}$II and III only

• D.$\hspace{1em}$I and III only

Which of the following is most likely to be the diameter of a carbon nucleus, if the diameter of a particular carbon atom is measured as 140 pm?

• A.$\hspace{1em}$ 12 amu

• B.$\hspace{1em}$ 0.0012 mm

• C.$\hspace{1em}$ 0.001 nm

• D.$\hspace{1em}$ 0.005 pm

In Rutherford’s gold foil experiment, some alpha particles bounced back towards the source. Which of the following statements best explains this result?

• A.$\hspace{1em}$ The atom consists mainly of empty space.

• B.$\hspace{1em}$ The atom has a positively charged center.

• C.$\hspace{1em}$ The atom consists of negative particles around the center.

• D.$\hspace{1em}$ The atom has a neutrally charged core.

Which of the following statements is not true?

• I.$\hspace{1em}$	Electrons have greater mass than protons and neutrons
  II.$\hspace{1em}$	Protons and neutrons are in the nucleus
  III.$\hspace{1em}$	Protons and electrons are charged subatomic particles
  IV.$\hspace{1em}$	Electrons are located outside the nucleus

• A.$\hspace{1em}$I and III only

• B.$\hspace{1em}$II and IV only

• C.$\hspace{1em}$II only

• D.$\hspace{1em}$I only

The nuclear symbol for an isotope of iodine is $\ce{^{125}_{53}I}$. Which of the following is correct?

A mass spectrometer was used to determine that the relative ratio by mass of N:O in a molecule containing nitrogen and oxygen is 7:16. What is the most likely molecule?

• A. $\hspace{1em}$ $\ce{NO}$

• B. $\hspace{1em}$ $\ce{NO2}$

• C. $\hspace{1em}$ $\ce{NO3}$

• D. $\hspace{1em}$ $\ce{N2O5}$

Which of the following is not a physical property of an isotope of an element with fewer neutrons in its atom?

• A.$\hspace{1em}$ Lower mass

• B.$\hspace{1em}$ Faster rate of diffusion

• C.$\hspace{1em}$ Higher density

• D.$\hspace{1em}$ Lower melting and boiling points

The isotopes of carbon $\ce{^{12}C}$ and $\ce{^{13}C}$:

• I.$\hspace{1em}$	have the same atomic number
  II.$\hspace{1em}$	have the same physical properties
  III.$\hspace{1em}$	have the same chemical properties

• A.$\hspace{1em}$I and III only

• B.$\hspace{1em}$I and II only

• C.$\hspace{1em}$II and III only

• D.$\hspace{1em}$I, II and III

How many electrons are there in $\ce{^{35}_{17}Cl^{1-}}$?

• A.$\hspace{1em}$ 17

• B.$\hspace{1em}$ 18

• C.$\hspace{1em}$ 35

• D.$\hspace{1em}$ 36

The following table shows the number of subatomic particles present in five species.

Species	Number of protons	Number of neutrons	Number of electrons
A	8	8	8
B	8	8	10
C	9	10	8
D	10	10	10
E	10	12	10

Which two species are isotopes of the same element?

• A.$\hspace{1em}$A and B

• B.$\hspace{1em}$B and C

• C.$\hspace{1em}$C and D

• D.$\hspace{1em}$D and E

The following table shows the number of subatomic particles present in five species.

Species	Number of protons	Number of neutrons	Number of electrons
A	8	8	8
B	8	8	10
C	9	10	8
D	10	10	10
E	10	12	10

Which species are ions?

• A.$\hspace{1em}$A and B

• B.$\hspace{1em}$B and C

• C.$\hspace{1em}$C and D

• D.$\hspace{1em}$D and E

Which of the following statements is incorrect?

• A.$\hspace{1em}$All ions contain electrons

• B.$\hspace{1em}$A few alpha particles deflected at large angles in Rutherford's Gold Foil experiment

• C.$\hspace{1em}$A mass spectrometer can tell us the number of isotopes an element has

• D.$\hspace{1em}$An atom can have more neutrons than protons

[Maximum mark: 5]

The atom of element X has a mass number of 127 and has 74 neutrons. The ion derived from X has 54 electrons.

1. Calculate the number of protons of element X. [1]
   

2. State the nuclear symbol of the ion formed (refer to the periodic table). [2]
   

3. An isotope of X has a mass number of 132. Determine the number of neutrons in its atom. [2]
   

The following is a hydrogen energy level diagram.

How many different emission lines are possible?

• A.$\hspace{1em}$1

• B.$\hspace{1em}$5

• C.$\hspace{1em}$15

• D.$\hspace{1em}$30

[Maximum mark: 8]

Deuterium is an isotope of hydrogen that contains one proton, one neutron, and one electron.

1. 1. Complete the following table. [2]
      
      

      	Protons	Neutrons	Electrons
      Relative charge
      Relative mass			~$\dfrac{1}{1836}$
      Location

      
      

   2. Using the following data, calculate the relative atomic mass of hydrogen correct to five decimal places, showing your work. [2]
      

      Isotope	Relative abundance
      Hydrogen-1	99.98%
      Deuterium	0.012%
      Hydrogen-3	0.008%

   
   

2. 1. Describe the emission spectrum of the hydrogen atom. [2]
      

   2. Outline the difference between a continuous spectrum and a line spectrum. [1]
      

   3. Suggest how your answer to (b)(i) shows that energy levels are quantized. [1]
      

[Maximum mark: 9]

Cobalt-60 is a radioactive isotope of the element cobalt that is used to treat thyroid cancer.

1. 1. State the full electron configuration of cobalt and chromium. [2]
      

   2. Explain what is special about the electron configuration of chromium. [1]
      

   3. State the atomic symbol notation for the cobalt-60 isotope. [1]
      

One atom of cobalt-60 undergoes beta decay, releasing an electron and energy with a frequency of $7.65\times10^{19} Hz$ to form nickel-60.

2. 1. Using section 1 of the data booklet, calculate the wavelength of energy released from beta decay. [1]
      

   2. Using section 3 (Section 5- 2025 Syllabus) of the data booklet and your answer to (b) (i), deduce the type of electromagnetic radiation emitted. [1]
      

3. 1. Define orbital. [1]
      

   2. Sketch the shapes of an s-orbital and a p-orbital. [2]
      

[Maximum mark: 5]

Complete the following table:

Nuclear Symbol	Number of protons	Number of neutrons	Number of electrons
$_{62}^{153}\textrm{Sm}$			62
	81	120
$_{26}^{56}\textrm{Fe}^{2+}$	26
$_{46}^{103}\textrm{Pd}$	46
	16	16	18

[Maximum mark: 7]

$\ce{^{63}_{}Cu}$ and $\ce{^{65}_{}Cu}$ are the two most abundant isotopes of copper.

1. 1. Define isotope. [1]
      

   2. Determine the correct numbers of subatomic particles to complete the following table. [1]
      

      	Copper-63	Copper-65
      Number of protons
      Number of electrons
      Number of neutrons

      
      

   3. Calculate the relative abundances of $\ce{^{63}_{}Cu}$ and $\ce{^{65}_{}Cu}$ using section 6 (Section 7- 2025 Syllabus) of the data booklet. [3]
      

2. Complete the orbital diagram for the valence electrons in a copper atom and a copper (II) ion. [2]
   

   

What is the smallest amount of energy an electron can release?

• A. $\hspace{1em}$ 0.31 $eV$

• B. $\hspace{1em}$ 0.54 $eV$

• C. $\hspace{1em}$ 10.19 $eV$

• D. $\hspace{1em}$ 13.59 $eV$

[Maximum mark: 5]

Lithium is a low-density alkali metal that reacts vigorously with water.

1. Given the below data and referring to the periodic table, calculate the relative abundances of the isotopes of lithium. [3]
   

Isotope	Atomic Mass
$^{6}\textrm{Li}$	6.015
$^{7}\textrm{Li}$	7.016

2. State the definition of an isotope. [1]
   

3. Outline the concept of relative abundance. [1]
   

[Maximum mark: 5]

Element Y has 4 stable isotopes. The table below shows the relative abundance and atomic masses of these isotopes.

Isotope	Percent abundance	Atomic mass
1	1.40 %	203.97
2	24.10 %	205.97
3	22.10 %	206.98
4	52.40 %	207.98

1. Calculate the relative atomic mass of the element. [2]
   

2. Identify the element. [1]
   

3. The atom of the element can form an ion with a charge of 4+. Determine the number of electrons in the ion. [1]
   

4. Determine the nuclear symbol of another corresponding ion of element Y given the numbers of subatomic particles: electrons = 80; neutrons = 122. [1]
   

What is the relative atomic mass, $\ce{A_r}$, of an unknown element found in a meteorite with the isotopic abundance shown below?

Isoptope	Abundance%
$X - 39$	80.0
$X - 40$	1.00
$X - 41$	19.0

• A. $\hspace{1em}$ 39.00

• B. $\hspace{1em}$ 40.00

• C. $\hspace{1em}$ 39.39

• D. $\hspace{1em}$ 40.50