AQA GCSE Chemistry (8462), Higher tier · Atomic structure and the periodic table › The periodic table
Practise The periodic table. 11 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
The position of an element in the periodic table is related to the arrangement of electrons in its atoms.
(a) Silicon has the atomic number 14. Explain how the position of silicon in the periodic table is related to the arrangement of electrons in its atoms.[3]
(b) Selenium, Se, is in Group 6, directly below sulfur. Sulfur burns in oxygen to form sulfur dioxide, SO2. Predict the formula of the compound formed when selenium burns in oxygen.[1]
(c) The formula of hydrogen sulfide is H2S. Predict the formula of hydrogen selenide.[1]
(d) Gallium is in Group 3 and Period 4. Give the number of electrons in the outer shell of a gallium atom and the number of occupied energy levels.[2]
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(a)Answer: Silicon is 2,8,4: three occupied energy levels so Period 3; four outer electrons so Group 4.
electronic structure is 2,8,4
three occupied energy levels / shells so it is in Period 3
four electrons in the outer shell so it is in Group 4
(b)Answer: SeO2
SeO2
(c)Answer: H2Se
H2Se
(d)Answer: 3 outer electrons; 4 occupied energy levels