Periodic Classification of Elements Science - Periodic Classification of Elements

According to Mendele′ ev's Periodic Law, the elements were arranged in the periodic table in the order of:

In Mendele′ ev ’s Periodic Table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the perioidc table later:

The element with atomic number 14 is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?

The elements A, B, C, D and E have atomic number 9, 11, 17, 12 and 13 respectively. Which pair of elements belong to the same group?

Which of the following elements would lose an electron easily?

Which one of the following elements exhibit maximum number of valence electrons?

1. Na.
2. Al.
3. Si.
4. P.

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

1. Atomic radius.
2. Metallic character.
3. Valence.
4. Number of shells in an element.

Which of the given elements A, B, C, D and E with atomic number 2, 3, 7, 10 and 30 respectively belong to the same period?

1. A, B, C.
2. B, C, D.
3. A, D, E.
4. B, D, E.

Which of the following statements about the Modern Periodic Table is correct:

1. It has 18 horizontal rows known as Periods.
2. It has 7 vertical columns known as Periods.
3. It has 18 vertical columns known as Groups.
4. It has 7 horizontal rows known as Groups.

Which of the following set of elements is written in order of their increasing metallic character?

1. Be Mg Ca.
2. Na Li K.
3. Mg Al Si.
4. C O N.

Identify and name the metals out of the following element whose electronic configurations are given below.
2, 1.

Identify and name the metals out of the following element whose electronic configurations are given below.
2, 8, 2.

Arrange the following element in increasing order of their atomic radii.
Cl, At, Br, I.

Identify the element with the following property and arrange them in increasing order of their reactivity:The metal which is an important constituent of limestone.

Arrange the following element in increasing order of their atomic radii.
Li, Be, F, N.

Identify the element with the following property and arrange them in increasing order of their reactivity:

The metal which is an important constituent of limestone.

Identify the element with the following property and arrange them in increasing order of their reactivity:

The metal which exists in liquid state at room temperature.

Identify the element with the following property and arrange them in increasing order of their reactivity:
An element which is a soft and reactive metal.

Identify and name the metals out of the following element whose electronic configurations are given below.
2, 8, 7.

Identify and name the metals out of the following element whose electronic configurations are given below.
2, 8, 2.

InMendele′ ev’s Periodic Table the elements were arranged in the increasing order of their atomic masses. However, cobalt with atomic mass of 58.93amu was placed before nickel having an atomic mass of 58.71amu. Give reason for the same.

Can the following groups of elements be classified as Dobereiner's triad?

1. Na, Si, Cl.
2. Be, Mg, Ca.

Atomic mass of Be 9; Na 23; Mg 24; Si 28; Cl 35; Ca 40. Explain by giving reason.

Three elements A, B and C have 3, 4 and 2 electrons respectively in their outermost shell. Give the group number to which they belong in the Modern Periodic Table. Also, give their valencies.

Elements have been arranged in the following sequence on the basis of their increasing atomic masses.
F, Na, Mg, Al, Si, P, S, Cl, Ar, K.

1. Pick two sets of elements which have similar properties.
2. The given sequence represents which law of classification of elements?

Three elements A, B and C have 3, 4 and 2 electrons respectively in their outermost shell. Give the group number to which they belong in the Modern Periodic Table. Also, give their valencies.

InMendele′ ev’s Periodic Table the elements were arranged in the increasing order of their atomic masses. However, cobalt with atomic mass of 58.93amu was placed before nickel having an atomic mass of 58.71amu. Give reason for the same.

Elements have been arranged in the following sequence on the basis of their increasing atomic masses.
F, Na, Mg, Al, Si, P, S, Cl, Ar, K.

1. Pick two sets of elements which have similar properties.
2. The given sequence represents which law of classification of elements?

Can the following groups of elements be classified as Dobereiner's triad?

1. Na, Si, Cl.
2. Be, Mg, Ca.

Atomic mass of Be 9; Na 23; Mg 24; Si 28; Cl 35; Ca 40. Explain by giving reason.

If an element X is placed in group 14, what will be the formula and the nature of bonding of its chloride?

Write the formulae of chlorides of Eka-silicon and Eka-aluminium, the elements predicted by Mendeleev.

The three elements A, B and C with similar properties have atomic masses X, Y and Z respectively. The mass of Y is approximately equal to the average mass of X and Z. What is such an arrangement of elements called as? Give one example of such a set of elements.

Write the formula of the product formed when the element A (atomic number 19) combines with the element B (atomic number 17). Draw its electronic dot structure. What is the nature of the bond formed?

“Hydrogen occupies a unique position in Modern Periodic Table”. Justify the statement.

Write the formula of the product formed when the element A (atomic number 19) combines with the element B (atomic number 17). Draw its electronic dot structure. What is the nature of the bond formed?

Write the formulae of chlorides of Eka-silicon and Eka-aluminium, the elements predicted by Mendeleev.

The three elements A, B and C with similar properties have atomic masses X, Y and Z respectively. The mass of Y is approximately equal to the average mass of X and Z. What is such an arrangement of elements called as? Give one example of such a set of elements.

If an element X is placed in group 14, what will be the formula and the nature of bonding of its chloride?

“Hydrogen occupies a unique position in Modern Periodic Table”. Justify the statement.

1. In this ladder (Figure) symbols of elements are jumbled up. Rearrange these symbols of elements in the increasing order of their atomic number in the Periodic Table.

2. Arrange them in the order of their group also.

Mendeleev predicted the existence of certain elements not known at that time and named two of them as Eka-silicon and Eka-aluminium.

1. Name the elements which have taken the place of these elements.
2. Mention the group and the period of these elements in the Modern Periodic Table.
3. Classify these elements as metals, non-metals or metalloids.
4. How many valence electrons are present in each one of them?

An element X (atomic number 17) reacts with an element Y (atomic number 20) to form a divalent halide.

1. Where in the periodic table are elements X and Y placed?
2. Classify X and Y as metal (s), non-metal (s) or metalloid (s)
3. What will be the nature of oxide of element Y? Identify the nature of bonding in the compound formed.
4. Draw the electron dot structure of the divalent halide.

An element X of group 15 exists as diatomic molecule and combines with hydrogen at 773K in presence of the catalyst to form a compound, ammonia which has a characteristic pungent smell.

1. Identify the element X. How many valence electrons does it have?
2. Draw the electron dot structure of the diatomic molecule of X. What type of bond is formed in it?
3. Draw the electron dot structure for ammonia and what type of bond is formed in it?

Arrange the following elements in the increasing order of their metallic character Mg, Ca, K, Ge, Ga.

Which group of elements could be placed in Mendele′ ev's Periodic Table without disturbing the original order? Give reason.

Properties of the elements are given below. Where would you locate the following elements in the periodic table?

1. A soft metal stored under kerosene.
2. An element with variable (more than one) valency stored under water.
3. An element which is tetravalent and forms the basis of organic chemistry.
4. An element which is an inert gas with atomic number 2.
5. An element whose thin oxide layer is used to make other elements corrosion resistant by the process of “anodising”.

1. In this ladder (Figure) symbols of elements are jumbled up. Rearrange these symbols of elements in the increasing order of their atomic number in the Periodic Table.

2. Arrange them in the order of their group also.

1. Electropositive nature of the element(s) increases down the group and decreases across the period.
2. Electronegativity of the element decreases down the group and increases across the period.
3. Atomic size increases down the group and decreases across a period (left to right).
4. Metallic character increases down the group and decreases across a period.

On the basis of the above trends of the Periodic Table, answer the following about the elements with atomic numbers 3 to 9.

1. Name the most electropositive element among them.
2. Name the most electronegative element.
3. Name the element with smallest atomic size.
4. Name the element which is a metalloid.
5. Name the element which shows maximum valency.

Mendeleev predicted the existence of certain elements not known at that time and named two of them as Eka-silicon and Eka-aluminium.

1. Name the elements which have taken the place of these elements.
2. Mention the group and the period of these elements in the Modern Periodic Table.
3. Classify these elements as metals, non-metals or metalloids.
4. How many valence electrons are present in each one of them?