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In the periodic table the atomic mass of elements usually increases as the atomic number increases - VCE - SSCE Chemistry - Question 2 - 2002 - Paper 1
Question 2
In the periodic table the atomic mass of elements usually increases as the atomic number increases. However, there are exceptions to this general rule. For example,... show full transcript
Worked Solution & Example Answer:In the periodic table the atomic mass of elements usually increases as the atomic number increases - VCE - SSCE Chemistry - Question 2 - 2002 - Paper 1
Step 1
How is it possible for the element with a smaller atomic number to have the greater relative atomic mass?
Answer
An element with fewer protons (lower atomic number) can have a higher relative atomic mass if it has more neutrons in its isotopes. For example, tellurium (atomic number 52) has several isotopes, some of which have a greater number of neutrons compared to iodine (atomic number 53). Thus, even though iodine has a higher atomic number, the presence of additional neutrons in tellurium causes its relative atomic mass to be greater.
Step 2
Why does a series of transition metals have 10 elements?
Answer
A transition series is formed by the progressive filling of a d subshell, which contains 10 orbitals. Each of these orbitals can hold two electrons, allowing for a maximum of 10 electrons in the d subshell, thus leading to the occurrence of 10 elements in each transition series.
Step 3
Choose one particular transition element. Give the formulas for two different compounds where this transition element shows different oxidation states.
Answer
One example of a transition element is iron (Fe). The formulas for two different compounds showing different oxidation states are:
- Compound 1: FeCl₂ (iron(II) chloride)
- Compound 2: FeCl₃ (iron(III) chloride)