Find the basis for giving names of the elements in the Table given below, and complete the table. Element The basis of naming Americium _____ Francium _____ Rubidium _____ Plutonium _____ Titanium _____ Mendelevium _____ Rutherfordium _____

Americium is named after a continent America where it was first made. Francium is named after a country France in Europe. Rubidium is derived form the Latin word 'rubidius', a colour which means the deepest red. Plutonium, is named after Pluto which was earlier considered as a planet. Titanium is named after the Greek mythological character- the son of the earth goddess whose name was Titan. Mendelevium is named after Dmitri Mendeleev who produced one of the first periodic tables. Rutherfordium is named after a scientist Ernest Rutherford, who was the first to explain the structure of atoms. Element The basis of naming Americium America — Continent Francium France — country Rubidium Ruby red — colour Plutonium Pluto — planet Titanium Titan — a Greek mythological character Mendelevium Dmitri Mendeleev — scientist Rutherfordium Ernst Rutherford — Scientist

In the table given below, write the number of molecules and the total number of atoms. Substance Number of molecules Total number of atoms O 2 2 N 2 6 Cl 2 2 He 5 Na O 3 P 4

O 2 is an oxygen molecule which is diatomic and consists of 2 atoms. Oxygen can't be found in its free form in the nature. Substance Number of molecules Total number of atoms O 2 1 2 2 N 2 is two molecules of nitrogen gas, which is a diatomic molecule. So the total number of atoms is 2 × 2 = 4 . Substance Number of molecules Total number of atoms 2 N 2 2 4 6 Cl 2 is 6 molecules of chlorine gas, which is a diatomic molecule. So the total number of atoms is 6 × 2 = 12 . Substance Number of molecules Total number of atoms 6 Cl 2 6 12 2 He contains 2 helium molecules. Helium is a mono atomic molecule. So the total number of atoms is 2 . Substance Number of molecules Total number of atoms 2 He 2 2 5 Na contains 5 sodium molecules. Sodium is a monatomic molecule. So the total number of atoms is 5 . Substance Number of molecules Total number of atoms 5 Na 5 5 O 3 is an ozone molecule. It is a polyatomic (triatomic) molecule. So the total number of atoms is 3 . Substance Number of molecules Total number of atoms O 3 1 3 P 4 is a phosphorus molecule. It is a polyatomic molecule. So the total number of atom is 4 . Substance Number of molecules Total number of atoms P 4 1 4

E M B I B E

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Exercise 2>Q 4

EASY

8th Kerala Board

IMPORTANT

Earn 100

One quarter of a boiling tube is filled with sugar and closed with cotton. Boiling tube is then heated strongly. What can be observed? What is seen on the sides of the boiling tube?

Important Questions on Basic Constituents of Matter

EASY

8th Kerala Board

IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Exercise 2>Q 5

What are the substances obtained by heating sugar?

EASY

8th Kerala Board

IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Exercise 2>Q 6

Find more examples of elements and list them.

EASY

8th Kerala Board

IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Exercise 3>Q 1

Compounds can be converted into its constituent elements through suitable chemical processes. Find more examples for compounds and note them in the science diary.

MEDIUM

8th Kerala Board

IMPORTANT

Science for Class 8 - Part 1>Chapter 5 - Basic Constituents of Matter>Exercise 3>Q 2

Find the basis for giving names of the elements in the Table given below, and complete the table.