An atom of an element is represented using nuclide notation. Fig. 1.1 shows the nuclide notation for one atom of this element. Fig. 1.1 (a) State what is me...
Question 1 Report
An atom of an element is represented using nuclide notation. Fig. 1.1 shows the nuclide notation for one atom of this element.
Fig. 1.1
(a) State what is meant by the term isotopes. [2]
(b) Use Fig. 1.1 to deduce the number of neutrons in this atom. [1]
(c) State the number of electrons in a neutral atom of this element. [1]
(d) A different isotope of the same element has a nucleon number of 35. State the number of neutrons in one atom of this isotope. [1]
(e) State one physical property that is different for the two isotopes. [1]
Answer Details
What this tests: the definition of isotopes and using nuclide notation to find neutrons and electrons.
(a) Isotopes [2] Isotopes are atoms of the same element [1] that have the same number of protons but different numbers of neutrons (same proton number, different nucleon numbers) [1].
(b) Neutrons [1] In nuclide notation the top number (37) is the nucleon number and the bottom number (17) is the proton number, so neutrons \(= 37 - 17 = 20\) [1].
(c) Electrons [1] A neutral atom has equal numbers of protons and electrons, so there are 17 electrons [1].
(d) Other isotope [1] With nucleon number 35, neutrons \(= 35 - 17 = 18\) [1].
(e) Different physical property [1] The two isotopes have different masses (accept different density or different rate of diffusion) [1]. Their chemical properties are identical because they have the same electron arrangement.
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