End Of July Test Exam 2021 S 3 Chemistry

1 | P a g e END OF JULY TEST EXAM 2021 S.3 CHEMISTRY DURATION: 2 hours TOPICS: ATOMIC STRUCTURE, BONDING, CARBON AND ITS COMPOUNDS. 1. (a) Define the following terms; (i) An atom ………………………………………………………………………………… ………………………………………………………………………………… (ii) Atomic number ………………………………………………………………………………… ………………………………………………………………………………… (iii) Ionic bond ………………………………………………………………………………… ………………………………………………………………………………… (iv) A cation ………………………………………………………………………………… ………………………………………………………………………………… (b) (i) In the space below, draw a well labelled diagram of an atom, showing the location of the 3 fundamental particles ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… (ii) Use the diagram above to explain why the nucleus of an atom is positively charged ………………………………………………………………………………… ………………………………………………………………………………… (c) In the space provided below; draw the electronic structure and write electronic configuration of the following (i) Magnesium atom (Mg) ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… 2 | P a g e (ii) Oxide ion (O2-) ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… (iii)Sodium ion (Na+) ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… 2. The number of electron, protons, and neutrons in the atoms of the elements x, y, z and v are shown below Atoms Electrons Protons Neutrons W 8 8 8 X 13 13 14 Y 16 16 16 z P 11 11 V 8 Q 16 a. Determine the value of; i. P……………………………………………………….. ii. Q ……………………………………………………… b. State the mass number of atom C c. Indicate with a reason, which atoms are; i. Isotopes ……………………………………………………………… Reason …………………………………………………………………………. ii. Belong to the same group in the periodic table. ………………………………………………………………………… Reason ………………………………………………………………………… d. Write the electronic configuration of ; (i) Atom C ………………………………………………………………. (ii) Ion of A ……………………………………………………………… (iii)Ion of B ……………………………………………………………….. 3. Given the table below. Element Atomic number X 5 Y 8 Z 11 W 17 q 12 a. Write the formula of the compound formed when; (i) X reacts with W ……………………………………………………. (ii) Y reacts with Z …………………………………………………….. 3 | P a g e (iii)W …