Lakhmir Singh solutions for Chemistry [English] Class 10 ICSE chapter 1 - Periodic Properties and Variations of Properties [null edition]

State whether the following statement is True or False.

Due to repetition of electronic configuration, repetition of properties takes place.

State whether the following statement is True or False.

Elements having the same number of electrons in the last shell lie in the same vertical column.

State whether the following statement is True or False.

Hydrogen and chlorine are placed in the same group.

State whether the following statement is True or False.

Lanthanides and actinides are placed in the third group.

At the time of Mendeleev, there were ______ elements known.

Group 17 elements are also called as ______.

Repetition of properties of elements with increasing atomic ______ is called periodicity.

The problems in Mendeleev periodic table were related to ______ of elements.

The horizontal and vertical rows in a periodic table are known as ______.

The arrangement of elements in the Modern Periodic Table is based on their ______.

What do you understand by electronic configuration?

How did the anomaly of putting isotopes together has been resolved in the modern periodic table?

Answer the following.

Why do the elements belonging to the same group have similar chemical properties?

Define the term periodicity.

State the modern periodic law for the classification of elements. How many (i) groups and (ii) periods are there in the modern periodic table?

State the limitation of the modern periodic table.

What were the criteria used by Mendeleev in creating his Periodic Table?

Write a short note on groups present in long form of periodic table.

Comment about the chemical properties of the elements of the same group.

State whether the following statement is True or False.

Electron affinity increases with a decrease in atomic size.

State whether the following statement is True or False.

Atomic radius decreases along a period.

State whether the following statement is True or False.

The tendency to lose electrons decreases as you move down a group.

Metallic character ______ down the group.

Valency of elements ______ and then ______ as we move across the period while it remains the same down the group.

The more is the ______ charge, the more will be the electron affinity.

The ______ radius is half the distance between the nuclei of two identical non-bonded adjacent atoms.

Which one of the following statements is not correct about the trends in the properties of the elements of a period on going from left to right?

An element X has mass number 40 and contains 21 neutrons in its atom. To which group of the Periodic Table does it belong?

Which one of the following statements is not correct about the trends in the properties of the elements of a group on going down in a group?

Define valence electrons.

How does non-metallic character vary in a period?

Which is the most electronegative element in the periodic table?

Why electron affinity decreases on moving downwards in the group?

Why does electron gain enthalpy has a negative value?

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

The atomic numbers of three elements, X, Y and Z are 9, 11 and 17 respectively. Which two of these elements will show similar chemical properties? Why?

How does the size of atoms (atomic size) generally vary in going from left to right in a period of the periodic table? Why does it vary this way?

F, Cl and Br are the elements each having seven valence electrons. Which of these (i) has the largest atomic radius, (ii) is most reactive? Justify your answer, stating the reason for each.

Why does chlorine has the highest electron gain enthalpy instead of fluorine?

The atomic number of an element is 16. Predict:

1. the number of valence electrons in its atom;
2. its valency;
3. its group number;
4. whether it is a metal or a non-metal;
5. the nature of the oxide formed by it.

How are the following related?

Number of valence electrons of different elements in the same group.

How are the following related?

Number of shells of elements in the same period.

How do the following change?

Number of shells of elements as we go down a group.

How do the following change?

Number of valence electrons of elements on moving from left to right in a period.

How do the following change?

Atomic radius in moving from left to right along a period.

How do the following change?

Atomic size down a group.

An ice cube made up of normal water floats in liquid water, while that made up of heavy water sinks in the normal liquid water. This is due to the fact that in heavy water, each molecule of water has two deuterium atoms instead of the two hydrogen atoms. Further, a deuterium atom differs from a hydrogen atom by the only fact that deuterium has one neutron in its nucleus along with one proton, while the hydrogen atom has only one proton in its nucleus.

Considering the fact that an extra neutron in the deuterium nucleus does not increase the volume ofthe heavy water molecule, estimate the percentage difference in densities of normal water and heavy water.

State whether the following statement is True or False.

Metals have a tendency for losing electrons and gaining a positive charge.

State whether the following statement is True or False.

The metallic character of alkalis decreases from lithium to francium.

State whether the following statement is True or False.

Halogens are strong oxidising agents since they easily accept electrons.

State whether the following statement is True or False.

Sodium combine with bromine to form electrovalent compound.

Elements which have an n/p ratio around ______ are stable.

Alkali metals form ______ compounds with non-metals.

Due to their high reactivity halogens exist as ______ molecules.

Atomic number is ______.

Mass number is ______.

Alkali metals are ______.

Halogens are ______.

Give two examples of alkaline earth metals?

How many valence electrons does a halogen have?

Which gas is liberated on the reaction of alkali metals with acid and water?

An element ‘Y’ has a mass number of 35 and a number of neutrons is 18. Find its group number and period.

Write two dissimilarities between alkali metals and halogens.

How does the electronegativity of halogen varies?

Whether halogens are oxidizing or reducing in nature, explain.

Differentiate mass number from atomic number.

Write five characteristic properties of alkali metals.

Write five characteristic properties of halogens.

Write the significance of atomic number.

We are surrounded by a variety of materials. Each of these materials are made up of elements that are listed in the periodic table. Make a poster fulfilling the guidelines mentioned below.

1. Select any ten elements of your choice from the first four periods of the periodic table.
2. Write the symbols, name and atomic number of these elements in a row.
3. Below each symbol, paste the images of materials that contain the element (represented above) as one of the significant components.
4. You cannot repeat the images of the same material for more than one element.

True or False.

The valency of an element of group 17 is 7.

True or False.

Noble gases have zero valency.

True or False.

Atomic radius of fluorine is greater than nitrogen.

True or False.

Calcium belongs to the fourth period of the periodic table.

True or False.

Silicon is an example of a non-metal.

Metallic nature of metals ______ from top to bottom in a group.

The tendency of an atom to attract the shared pair of electrons towards itself while forming a chemical bond is known as ______.

______ is the most electronegative element in the periodic table.

______ has the largest atomic size in the third period of the periodic table.

All the elements present on the left side and in the middle of the periodic table are metallic in nature except ______.

In the periodic table, elements of period 3 are arranged in increasing order of ionisation energy as:

Elements X and Y have atomic numbers 13 and 8, respectively. The chemical formula of the compound formed will be:

Alkaline earth metals have the same ______.

An element ‘X’ with atomic number 19 will ______.

Elements having similar valence shell configurations are placed in ______.

Which of the following has the largest atomic size?

Which of the following shows diagonal relationship with Beryllium?

The non-metallic character in a period:

Group 1 and 2 elements are strong metals because ______.

Which of the following is the correct decreasing order of metallic character?

From the given set of metals and non-metals, identify the set with only non-metals.

Which of the following groups contains metals, non-metals and metalloids?

Which of the following elements is a metalloid?

Silicon is a metalloid because ______.

Match the following columns and choose the correct option.

Match the following columns and choose the correct option.

Explain the differences in properties of alkalis and halogens.

Give reason:

Why atomic number of an element is more important than its relative atomic mass?

Explain why all the elements of a group have similar chemical properties.

Explain why all the elements of a period have different chemical properties.

Write two reasons responsible for the late discovery of noble gases?

How many groups and periods are there in the modern periodic table?

How do the atomic size and metallic character of elements vary as we move?

1. down a group and
2. from left to right in a period

The metals in Group 2 from top to bottom are: Be, Mg, Ca, Sr, Ba and Ra. Which of these metals will form ions most readily and why?

What property of an element is measured by electro negativity?

An element 'M' with electronic configuration (2, 8, 2) combines separately with (NO₃)^–, (SO₄)^2– and (PO₄)^3– radicals. Write the formula of the three compounds so formed. To which group and period of the Modern Periodic Table does the element 'M' belong? Will 'M' form covalent or ionic compounds? Give reason to justify your answer.

Arrange the following as per the instruction given in the brackets:

He, Ar, Ne (Increasing order of the number of electron shells)

Arrange the following as per the instruction given in the brackets:

Na, Li, K (Increasing Ionisation Energy)

Arrange the following as per the instruction given in the brackets:

F, Cl, Br (Increasing electronegativity)

Arrange the following as per the instruction given in the brackets:

Na, K, Li (Increasing atomic size)

The following questions refer to the Periodic Table.
Name the first and last element in period 2.

The following questions refer to the Periodic Table.
What happens to the atomic size of elements moving from top to bottom of a group?

The following questions refer to the Periodic Table.
Which of the elements has the greatest electron affinity among the halogens?

The following questions refer to the Periodic Table.
What is the common feature of the electronic configurations of the elements in group 7?

Consider the section of the periodic table given below:

Note: In this table B does not represent boron

C does not represent carbon

F does not represent fluorine

H does not represent hydrogen

K does not represent potassium

You must see the position of the element in the periodic table.

Some elements are given in their own symbol and position in the periodic table, while others are shown with a letter. With reference to the table answer the following:

1. Which is the most electronegative?
2. How many valence electrons are present in G?
3. Write the formula of the compound between B and H.
4. In the compound between F and J, what type of bond will be formed?
5. Draw the electron dot structure for the compound formed between C and K.

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

Which element has the electronic configuration 2, 8, 1?

Name the element which has a total of three shells with five electrons in its valence shell?

Which element has a total of two shells, with four electrons in its valence shell?

Which element has twice as many electrons in its second shell as in its first shell?

A group of elements in the periodic table is 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:

1. Which element has the most metallic character?
2. Which element would be expected to have the highest electronegativity?
3. If the electronic configuration of aluminium is 2, 8, 3, how many electrons will be there in the outermost shell of thallium?
4. The atomic number of boron is 5. Write the chemical formula of the compound formed when boron reacts with chlorine.
5. Will the elements in the group to the right of this boron group be more metallic or less metallic in character? Justify your answer.

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

Li, Be, B, C, O, F, Ne

1. To which period do these elements belong?
2. One element ofthis period is missing. Which is the missing element and where should it be placed?
3. Which one of the elements in this period shows the property of catenation?
4. Place the three elements fluorine, beryllium and nitrogen in the order of increasing electronegativity.
5. Which one of the above elements belongs to the halogen series?

The atomic number of an element is 15. Predict

1. the number of valence electrons present in its atom.
2. its valency.
3. its group number.
4. whether it shows metallic or non-metallic properties.
5. the nature of the oxide formed by it.
6. the formula of the chloride.

From the list of characteristics given below, select the five which are relevant to non-metals and their compounds:

1. Ductile
2. Conduct electricity
3. Brittle
4. Acidic Oxides
5. Basic Oxides
6. Discharged at anode
7. Discharged at cathode
8. Ionic chlorides
9. Covalent chlorides
10. Reaction with dilute sulphuric acid yields hydrogen
11. 1, 2 or 3 valence electrons
12. 5, 6, 7 valence electrons

(Write the five letters corresponding to the correct characteristics).

Define the term ‘ionisation potential`.

Define the term ‘electron affinity’.

Atomic number of an element is 16. State

1. the period to which it belongs
2. the number of valence electrons
3. whether it is a metal or non-metal

In the above table, H does not represent hydrogen.Some elements are given in their own symbol and position in the periodic table while others are shown with a letter. With refrence to the table answer the following questions.
1. Identify the most electronegative element.
2. Identify the most reactive element of Group I.
3. Identify the element from Period 3 with least atomic size.
4. How many valence electrons are present in Q?
5. Which element from group 2 would have the least ionisation energy?
6. Identify the noble gas of the fourth period.
7. In the compound between A and H, what type of bond would be formed and give its molecular formula.

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?

Arrange the following as per the instruction given in the bracket:

Cs, Na, Li, K, Rb (increasing order of metallic character).

Arrange the following as per the instruction given in the bracket:

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

Arrange the following as per the instruction given in the bracket:

Na, K, Cl, S, Si (increasing order of ionization energy)

Arrange the following as per instruction given in the bracket.
Cl, F, Br, I (increasing electron affinity)

Use the letters only written in the Periodic Table given below to answer the questions that Follow:

1. State the number of valence electrons in atom J.
2. Which element shown forms ions with a single negative charge?
3. Which metallic element is more reactive than R?
4. Which element has its electrons arranged in four shells?

Fill in the blank by selecting the correct word from the option.
If an element has a low ionization energy then it is likely to be ________ 

Fill in the blank by selecting the correct word from the bracket.
If an element has seven electrons in its outermost shell then it is likely to have the _____ atomic size among all the elements in the same period.

In Period 3 of the Periodic Table, element B is placed to the left of element A. On the basis of this information, choose the correct word from the option to complete the following statement:

The element B would have ______ metallic character than A.

In Period 3 of the Periodic Table, element B is placed to the left of element A. On the basis of this information, choose the correct word from the option to complete the following statement:

The element A would probably have ______ electron affinity than B.

In Period 3 of the Periodic Table, element B is placed to the left of element A. On the basis of this information, choose the correct word from the option to complete the following statement:

The element A would have ______ atomic size than B.

Name the following element.

An alkaline earth metal present in group 2 and period 3.

Name the following element:

A trivalent metal used to make light tools.

Name the following element:

A monovalent non-metal present in fluorspar.

The following table represents the elements and atomic number. With reference to this, answer the following using only the alphabets given in the table.

1. Which element combines with hydrogen to form a basic gas?
2. Which element has an electron affinity zero?
3. Name the element which forms an ionic compound with chlorine.