Chemistry
A group of elements in the Periodic Table are given below (boron is the first member of the group and Thallium is the last).
Boron, Aluminium, Gallium, Indium, Thallium
Answer the following questions in relation to the above group of elements :
(a) Which element has the most metallic character ?
(b) Which element would be expected to have the highest electronegativity ?
(c) If the electronic configuration of aluminium is 2, 8, 3, how many electrons are there in the outer shell of thallium ?
(d) The atomic number of boron is 5. Write the chemical formula of the compound formed when boron reacts with chlorine.
(e) Will the elements in the group to the right of this boron group be more metallic or less metallic in character ? Justify your answer.
Periodic Table
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Answer
(a) Thallium has the most metallic character as metallic character increases on moving down the group.
(b) Boron has the highest electronegativity because the electronegativity decrease on moving down the group.
(c) There are 3 electrons in the outer shell of thallium because all the elements in a group have same number of valence electrons.
(d) BCl3 (Boron Chloride).
Boron needs 3 electrons while each chlorine atom can donate one electron. So 3 chlorine atoms donate 1 electron each to react with 1 Boron atom forming BCl3 (Boron Chloride).
(e) The elements in the group to the right of this boron group are less metallic because on moving left to right in a period metallic character decreases as atomic size decreases the electrons are strongly bound with the atom so it becomes more difficult to lose an electron.
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Related Questions
Name the periodic property which relates to the:
(a) amount of energy required to remove an electron from an isolated gaseous atom,
(b) character of element which loses one or more electrons when supplied with energy,
(c) tendency of an atom in a molecule to attract the shared pair of electrons.
This question refers to the elements of the Periodic Table with atomic numbers from 3 to 18. Some of the elements are shown by letters, but the letters are not the usual symbols of the elements.
3 4 5 6 7 8 9 10 A B C D E F G H 11 12 13 14 15 16 17 18 I J K L M N O P Which of these :
(a) is the most electronegative element ?
(b) is a halogen ?
(c) is an alkali metal ?
(d) is an element with valency 4 ?
(e) have least Ionisation Energy.
(f) have least atomic size in period 3.
In the periodic table, alkali metals are placed in the group:
- 1
- 11
- 17
- 18
Which of the following properties does not match with the elements of the halogen family ?
- They have seven electrons in their valence shell.
- They are highly reactive chemically.
- They are metallic in nature.
- They are diatomic in their molecular form.