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प्रश्न
An element has its electron configuration as 2,8,8,2. Now answer the following questions.
a) What is the atomic number of this element?
b) What is the group of this element?
c) To which period does this element belong?
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उत्तर
a) The atomic number of this element is 20.
b) The group of this element 2.
c) This element belongs to fourth period.
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संबंधित प्रश्न
Name two metals which are found in nature in the free state.
What chemical process is used for obtaining a metal from its oxide?
Metallic oxides of zinc, magnesium and copper were heated with the following metals.
| Metal | Zinc | Magnesium | Copper |
| Zinc oxide | – | – | – |
| Magnesium oxide | – | – | – |
| Copper oxide | – | – | – |
In which cases will you find displacement reactions taking place?
A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset, but after a futile argument, the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
Name one metal which is extracted by electrolytic reduction.
Give the name of one ore of iron. Which iron compound is present in this ore? Write its chemical formula.
The two metals which can be extracted just by heating their sulphides in air are:
(a) sodium and copper
(b) copper and aluminium
(c) potassium and zinc
(d) mercury and copper
Which of the following metals are extracted by the electrolysis of their molten chlorides?
(a) Na and Hg
(b) Hg and Mg
(c) Na and Mg
(d) Cu and Fe
The metal which can be extracted from pyrolusite ore is:
(a) mercury
(b) manganese
(c) aluminium
(d) magnesium
Name the following:
Two metals which are found in the free or native state.
Complete the incomplete statement with missing word:
Metals are malleable while non-metals are ______.
How many valence electrons are present in non- metals?
Name a non- metal that has a metallic luster and sublimes on heating.
_______ is the least reactive metal.
Write the molecular formulae of the following compound.
Cryolite
Explain the following reaction with the balanced equation.
Dry aluminium hydroxide is ignited at 1000 °C
Explain concept with example/explain with the help of a balanced equation.
Roasting
Complete flow chart given below.
Read the following passage and answer the questions.
According to the reactivity series, zinc is more reactive than iron, iron is more reactive than silver. During study of this, a student dipped the iron nails in silver nitrate solution.
- What is reactivity series?
- What will happen when iron nails are dipped in silver nitrate solution?
- Which type of reaction happens when iron metal reacts with silver nitrate solution?
- What will happen if a zinc rod is used instead of iron nail?
Assertion (A): The extraction of metals from their sulphide ores cannot take place without roasting the ore.
Reason (R): Roasting converts sulphide ores directly into metals.
