The Periodic Table of Elements

Question 7:Chlorine, Cl2 reacts with sodium, Na to form a compound. Write the chemical equation for the reaction. Answer:2Na(s) + Cl2(g) → 2NaCl(s) Question 8:Figure 3 shows the electron arrangement for the element G.(a) Which group does element G belong to in the Periodic Table of Elements? (b) Which period does element G belong to … Read more

Question 1:How did Moseley arrange the elements in the Periodic Table of Elements? Answer:According to increase in proton number Question 2:Figure 1 shows the chemical symbol for element X.(a) Which group does element X belong to in the Periodic Table of Elements?(b) Which period does element X belong to in the Periodic Table of Elements? … Read more

Question 1:Table 4.13 shows three transition elements that exist in gems.(a) What are the special characteristics of the transition elements shown in Table 4.13?(b) Apart from the characteristics given in 1(a), what are the other characteristics found in transition elements? Answer:(a) Transition elements form coloured ions(b) Have different oxidation numbers / form complex ions Question … Read more

Question 1:Why are the elements sodium, Na, magnesium, Mg, aluminium, Al, silicon, Si, phosphorus, P, sulphur, S, chlorine, Cl and argon, Ar in the same period? Answer:These elements have three electron shells. Sodium, Na (2.8.1), magnesium, Mg (2.8.2), aluminium, Al (2.8.3), silicon, Si (2.8.4), phosphorus, P (2.8.5), sulphur, S (2.8.6), chlorine, Cl (2.8.7) and argon, … Read more

Experiment 4.2:Aim: To study the change of chemical properties of oxides of elements across Period 3.Problem statement: How does the chemical properties of oxides of elements change across Period 3?Materials: Sodium oxide, Na2O, magnesium oxide, MgO, aluminium oxide, Al2O3 sulphur dioxide gas, SO2, silicon(IV) oxide, SiO2, distilled water, 2.0 mol dm–3 sodium hydroxide, NaOH and … Read more

Question 1:State three physical properties of elements down the Group 17. Answer:• The melting point and boiling point increases• The colour becomes darker• The density increases Question 2:Fluorine is very reactive compared to iodine. The reaction of fluorine with almost all other elements is very vigorous. Why is fluorine more reactive compared to iodine? Answer:The … Read more

Question 1:Give two examples of Group 1 elements. Answer:Lithium and rubidium (any Group 1 element) Question 2:Table 4.5 shows the electron arrangement for elements X, Y and Z.(a) Give two differences in physical properties between elements X, Y and Z.(b) Element X reacts with oxygen when heated. Write the chemical equation for this reaction.(c) Arrange … Read more

Experiment 4.1:Aim: To study the chemical properties of Group 1 elements.Problem statement: What are the chemical properties of Group 1 elements, when they react with water, oxygen gas and chlorine gas?Materials: Lithium, sodium, potassium, distilled water, filter paper, red litmus paper, oxygen and chlorine gasApparatus: Forceps, white tile, basin, knife, combustion spoon, gas jar with … Read more

Question 1:State the electron arrangement of helium, He. Answer:2 Question 2:What is the type of electron arrangement of argon atom, Ar? Answer:Octet Question 3:Explain why neon, Ne does not react with other elements. Answer:The neon atom has a stable octet arrangement of electrons Question 4:Compare the boiling point of helium and argon. Explain. Answer:The size … Read more

Question 1:Write the symbols for magnesium, copper and fluorine. Answer:Mg, Cu, F Question 2: State the electron arrangement and group, for each of the following elements. Refer the Data Table of Elements on page 276 to get the proton number of each element. (a) Potassium, K (b) Carbon, C (c) Chlorine, Cl(d) Argon, Ar Answer:(a) 2.8.8.1; … Read more