INTERNATIONAL INDIAN SCHOOL, RIYADH SA-II WORKSHEET GRADE-X – CHEMISTRY Chapter:-Periodic classification of elements 1. An element ‘X’ is in second period and group 16 of the periodic table. 1) Is it a metal or a non-metal? 2) What is the valency 3) What will be the formula of the compound of ‘X’ with Na.? 4) What is the name of the element? 2. An element ‘X’ belongs to the Second group of the periodic table. What is the formula of its chloride and oxide? 3.Table given below shows a part of the periodic table. H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar Using this table explain why (a) Li and Na are considered as active metals (b) Atomic size of Mg is less than that of Na (c) Fluorine is more reactive than chlorine 4. An element belongs to 4th period and group 17 of the periodic table. Find out 1) The number of valence electrons 2) Is it a metal or non-metal 3) name the element 4) Formula of its compound with hydrogen 5) electron dot structure of this element with calcium 5.(i) What is the position of hydrogen in the modern periodic table? (ii) Where are isotopes of the same element having different atomic masses placed in the periodic table? 1 |I I S R W o r k s h e e t s / X / S A 2 / C h e m i s t r y / 2 0 1 4 ‐ 2 0 1 5 6. How would the following properties of the element vary along the Period from left to right in the modern periodic table. Give reason. (1)Tendency to lose electrons (2) Atomic size (3)valency 7. How many groups and periods are there in modern periodic table. Justify the placement of oxygen(At No.8) Sulphur (At No.16) and selenium (At No.34) in the same group which of thee elements are present in ores to maximum extent? 8.(i)Magnesium Oxide is MgO. What is the formula of Magnesiuim hydroxide and Magnesium sulphate? (ii)Which is more reactive Mg or Ca and Why? 9. (a) Flurine is more reactive than chlorine why? (b) Ne has zero valency. Why? (c)Mg is more metallic than Be .Why? 10. ‘A’ and ‘B’ belong to group 2 and 13 respectively in 2nd period. (a) Which of them is smaller (b)Which of them can lose electron easily ( c) Give formula of their oxides and chlorides. 11.Two elements X and Y belong to group 2 respectively in the same period of the periodic table. Compare them with respect to (i) (ii) (iii) (iv) (v) The number of valence electrons in their atoms Their valencies Metallic character The size of their atoms The formula of their oxides and chlorides. 12. The elements of the third period of the periodic table are given below. Group I II III IV V VI VII Period Na Mg Al Si P S Cl (a) Which atom is bigger, Na or Mg? Why? (b) Identify the most metallic and non-metallic element in period 3 13. The atomic numbers of three elements A,B,C are given below. Element Atomic Number A 5 B 7 C 10 2 |I I S R W o r k s h e e t s / X / S A 2 / C h e m i s t r y / 2 0 1 4 ‐ 2 0 1 5 (a)Which element belong to group 18 (b) Which element belong to group 15 (c)Which element belong to group 13 (d) To which periods do these elements belong? 14. (i) Which can lose electrons easily? K or Na? Why? (ii) Which can gain electron easily O or F? Why? 15.Compare the radii of two species X and Y .Give reasons for your answer. ( a) X has 12 protons and 12 electrons ( b) Y has 12 protons and 10 electrons 16. Write the formula of the product formed when the element A( At No.19) Combines with the element B(At No17) . Draw its electron dot structure. What is the nature of the bond formed. 17. Arrange the following elements in increasing order of their atomic radii (a) Li , Be, F, N (b) Cl, At, Br, I 3 |I I S R W o r k s h e e t s / X / S A 2 / C h e m i s t r y / 2 0 1 4 ‐ 2 0 1 5