Deduce the number of electrons, protons and neutrons in ${}_{38}{}^{58}\mathrm{Ce}^{3+}$.

Read the paragraph in 'Developing an idea: Nanomachines' at the beginning of this chapter about Rutherford's work in discovering the nucleus.

Use your knowledge of what you have learned in this chapter to think about any other experiments that could have been used. 

Boron is an element in Group 13 of the Periodic Table.

Boron has two isotopes. 

Deduce the number of i) protons, ii) neutrons and iii) electrons in one neutral atom of the isotope${}_5{}^{11}\mathrm{B}$ . 

Boron is an element in Group 13 of the Periodic Table.

Boron has two isotopes. 

What do you understand by the term isotope?

Boron is an element in Group 13 of the Periodic Table. Boron has two isotopes. 

State the relative masses and charges of i) an electron ii) a neutron iii) a proton

Zirconium, $\mathrm{Zr}$, and hafnium, $\mathrm{Hf}$, are metals. An isotope of zirconium has 40 protons and 91 nucleons. 

i) Write the isotopic symbol for this isotope of zirconium. 
ii) State the number of neutrons present in one atom of this isotope. 
 

Zirconium, $\mathrm{Zr}$, and hafnium, $\mathrm{Hf}$, are metals.

The symbol for a particular ion of hafnium ion is ${}_{72}{}^{180}\mathrm{Hf}^{2+}$. Deduce the number of electrons that are present in one of these hafnium ions.