Element A belongs to group 15 and period 2 of the Periodic Table.
(a) Identify the element A.
(b) Write the formula of the compound formed when element A combines with hydrogen.
(c) Draw the dot (•) and cross (×) structure of the compound formed in (b) above.
(a) Element A is Nitrogen (N) with electronic configuration 2, 5.
(b) Nitrogen has a valency of 3 and combines with hydrogen (valency 1) to form ammonia (NH3).
(c) Dot (•) and cross (×) structure of NH3:
More ICSE Moderate level questions
Elements P, Q, and R are in the same period of the modern periodic table. P readily loses its one valence electron to form a stable ion. Q shares its electrons in bonding but does not form ions easily. R has high electronegativity. Answer the following questions based on the above information: (a) Which element would be most difficult to reduce among P, Q and R? (b) Which element is expected to have the smallest atomic radius among P, Q and R? (c) Arrange P, Q and R in order of decreasing ionisation potential.
Given below are a few elements. Li, Li, K, Ca, F Identify the element which: (a) has the least atomic radius. (b) has two valence electrons. (c) is the most electropositive.
Give reasons why: (a) Hydrochloric acid cannot form an acid salt. (b) Electronegativity increases across a period.
Complete the following sentences by choosing the correct option from the brackets: (a) The oxide that dissolves in caustic potash (KOH) is ............... . [ZnO / CuO] (b) The reaction that takes place at the anode during the electrolysis of molten lead bromide is ............... . [2Br − 2e− ⟶ 2Br− / 2Br− − 2e− ⟶ Br2] (c) The volume occupied by 8 grams of oxygen gas at STP is ............... litres. [5.6 / 8.96] [Atomic weight of O = 16] (d) ............... does not give hydrogen gas when it reacts with cold and very dilute nitric acid. [Cu / Mn] (e) ............... is a polar covalent compound. [HCl / CCl4]
Identify the following terms / compounds: (a) A compound which reacts with water to give acetylene gas. (b) The gas evolved when sodium propanoate is heated with soda lime. (c) A reddish-brown precipitate formed when ferric chloride solution reacts with an alkali. (d) A pair of electrons present in an atom which is not shared with any other atom during bond formation. (e) The relative molecular mass of a substance expressed in grams.
Name the following: (a) The most electronegative element of Period 2. (b) The largest atom of Period 3.
Arrange the following as per the instruction given in the brackets: (a) Al, K, Mg, Ca (decreasing order of its reactivity) (b) N, Be, O, C (increasing order of non-metallic character) (c) P, Si, F, Be (decreasing order of valence electrons)
Choose the answer from the list which fits in the description: [CCl4, PbO, NaCl, CuO, NH4Cl] (a) A compound which undergoes thermal dissociation. (b) An amphoteric oxide. (c) A compound which is a non-electrolyte.
Study the table given below. Use only the letters given in the table to answer the questions. Do not identify the elements. IA IIA IIIA IVA VA VIA VIIA 0 E J Q L G M D P N (a) State the valency of element ‘G’. (b) Which element can exhibit catenation? (c) Write the formula of the compound formed between ‘M’ and ‘P’.
Draw the dot and cross structure of the following: (a) An ionic compound formed when Mg reacts with the dilute HCl. (b) A covalent compound formed when H2 reacts with Cl2. (c) The positive ion produced when ammonia gas is dissolved in water. [ Atomic number: Mg = 12, Cl = 17, H = 1, N = 7 ]
Identify the following: (a) An element in period 1 which can be placed in both group 1 and group 17 of the Periodic Table. (b) The element having electronic configuration 2, 8, 6. (c) The most electronegative element of period 3.
Arrange the following as per the instructions given in the brackets: (a) Carbon, Fluorine, Beryllium (decreasing order of atomic size) (b) Sulphuric acid, Phosphoric acid, Acetic acid (increasing order of number of replaceable H atoms per molecule) (c) Potassium, Lithium, Sodium (increasing order of ionization potential)
