Classify the following elements into metals, non-metals and metalliods As, C, Hg, Mg, S, Si - Science and Technology 1


Classify the following elements into metals, non-metals and metalliods

As, C, Hg, Mg, S, Si



Metals Non-metals Metalloids
Hg C Si
Mg S As
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2014-2015 (March)



Fill in the blank:

The formulae of chloride of metal M is MCl2. The metal M belongs to ……………. group.

Elements in the same group show the same valency. Give scientific reason.

Write the electronic configuration of K and Ne.

The atomic masses of three elements A, B and C having similar chemical properties are 7, 23 and 39, respectively.

  1. Calculate the average atomic mass of elements A and C.
  2. Compare the average atomic mass with atomic mass of B.
  3. What could the elements A, B and C be?

Na, Mg and Al are the elements of the same period of Modern Periodic Table having, one, two and three valence electrons respectively. Which of these elements (i) has the largest atomic radius, (ii) is least reactive? Justify your answer stating reason for each case.

List any two properties of the elements belonging to the first group of the modern periodic table.

Based on the group valency of elements state the formula lot the following giving justification for each :-

(i) Oxides of 1st group elements,

(ii) Halides of the elements of group 13, and

(iii) Compounds formed when an element of group 2 combines with, an element of group 16.

Define the term : Valency

 Which element has two shells, both of which are completely filled with electrons?

An element Z has atomic number 16. Answer the following questions on Z:

1) State the period and group to which Z belongs

2) Is Z a metal or a non-metal?

3) State the formula between Z and hydrogen

4) What kind of a compound is this?

Differentiate between Normal elements and Transition elements.

In the following set of element, one element does not belong to the set. Select this element and state why it does not belong:
Calcium, Magnesium, Sodium, Beryllium

Five elements A, B, C, D and E have atomic numbers of 2, 3, 7, 10 and 18 respectively. The elements which belong to the same period of the periodic table are:

(a) A, B, C
(b) B, C, D
(c) A, D, E
(d) B, D, E

The atomic numbers of the elements Na, Mg, K and Ca are 11, 12, 19 and 20 respectively. The element having the largest atomic radius is:

(a) Mg
(b) Na
(c) K
(d) Ca

Which one of the following does not increase while moving down the group of the periodic table?

What do you understand by? 


Name two elements you would expect to show chemical reactions similar to calcium. What is the basis of your choice?

State the valency of the elements of periods 3 and write the formula of their oxides.

An element X belong to 4th period and 17th group, state.

no of valence electrons in it

name the elements in period 1.

Four elements P, Q, R and S belong to the third period of the Modern Periodic Table and have respectively 1, 3, 5 and 7 electrons in their outermost shells. Write the electronic configurations of Q and R and determine their valences. Write the molecular formula of the compound formed when P and S combine.


How do you calculate the possible valency of an element from the electronic configuration of its atoms?

Atomic number of metal ‚A‛ is 11, while atomic number of metal ‚B‛ is 20. Which of them will be more reactive? Write the chemical reaction of dilute HCl  with metal ‚A‛.

Taking into consideration the period of the elements given below, answer the following questions: 

Elements Atomic Radius (pm)
O 66
B 88
C 77
N 74
Be 111
Li 152
  1. Arrange the above elements in decreasing order of their atomic radii.
  2. State the period to which the above elements belong.
  3. Why this arrangement of elements is similar to the above period of modern periodic table?
  4. Which of the above elements have the biggest and the smallest atom?
  5. What is the periodic trend observed in the variation of atomic radius while going from left to right within a period?

What is meant by periodicity of elements?

Size of atom changes when it loses or gain electron

Arrange the following as per instruction given in the bracket.

Mg, Cl, Na, S, Si (decreasing order of atomic size) 

The elements of one short period of the periodic table are given below in order from left to right: 

Li Be B C O F Ne 

Place the three elements: Fluorine, Beryllium and nitrogen in the order of increasing electronegativity

The position of elements A, B, C, D and E in the periodic table are shown below:

Group 1

Group 2

Group 17

Group 18













State which is most reactive (i) metal (ii) non-metal


The position of elements A, B, C, D and E in the periodic table are shown below:

Group 1

Group 2

Group 17

Group 18













Which type of ion will be formed by elements A, B, and C.


An element belongs to the third period and Group IIIA (13) of the periodic table. State: if it is a metal or non-metal?

Name and state the following with reference to the elements of the first three periods of the periodic table.

Valency of elements in Group 14 and 15.

Write down the word that will correctly complete the following sentence:

Moving left to right in the second period, the number of valence electrons _____. 

An element A has 2 electrons in its fourth shell. State:

its valency

(a) Fill in the blanks and rewrite the completed statements: 

(i) ________ group in the periodic table contains elements that are all gases at room temperature. 

(ii) Very fine particles mainly scatter ______ light.

Fill in the blank and rewrite the completed statement:

________ group in the periodic table contains elements that are all gases at room temperature.

Give Scientific Reason:
Atomic size increase down the group.

Answer the following question:
State the four blocks of the modern periodic table based on the electronic configuration of elements.

Supply the missing word from those in bracket:

If an element has one electron in its outermost energy level [shell] then it is likely to be _______.

Name or state following with reference to the element of the first three periods of the periodic table.

The valency of elements in group 1 [I–A].

Give a reason for the following:

A transition from metallic to non-metallic elements is seen on moving from left to right in a period of the periodic table.

State the following:

The group to which the element with an electronic configuration of 2, 8, 2 belongs.


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