Answer the following questions in detail.
1. An atom X that has 12 protons and 12 electrons, loses two electrons to form an ion. What will be the charge on the ion? What will be the number of protons and electrons in the ion?
2. An element Y that has 17 protons and 17 electrons it gains one electron to form an ion. What will be the charge on the ion? Write the number of protons and electrons in Y
3. Write the differences between iron-sulphur mixture and iron sulphide compound.
4. The formula of lead nitrate is Pb(NO), What is the ratio in which three elements combine with each other in this compound?
5. How many atoms of hydrogen are present in one molecule of the following compounds: (NH), SO, NH, NH CONH,
6. Write the chemical formulae for the following compounds:
Magnesium chloride, Zinc sulphide, Sodium sulphate, Calcium bicarbonate.
7. What is a chemical equation? Explain with an example.
8. The chemical formulae of several substances are listed below:
CaF, AI,O,Ba, HNO, Cu, Mgo
a. Classify the substances as element or compound.
b. Name the elements present in each of the compounds listed above.
Answers
Answer:
1.The charge on the ions after losing two ions will be +2.The number of protons will be 12 and electron will be 10.
2.Neutral atoms can be turned into positively charged ions by removing one or more electrons. A neutral sodium atom, for example, contains 11 protons and 11 electrons. By removing an electron from this atom we get a positively charged Na+ ion that has a net charge of +1.
Atoms that gain extra electrons become negatively charged. A neutral chlorine atom, for example, contains 17 protons and 17 electrons. By adding one more electron we get a negatively charged Cl- ion with a net charge of -1.
Answer:
Ans->1] Given that an atom X has 12protons and 12electrons.
Itloses 2 electrons to form an ion
We need to find the charge and the number of protons and electrons after formation of ions
Solution:
When the atoms loses 2 electrons then the atom comprises of 10 electrons.
Hence the ion will have
Charge: two-unit positive charge
No. of proton = 12
No. of electron = 10
Valency = 2
Valence electron = 12
Ans=>2] The atomic number is the number of electrons present in an atom. We know that an atom has the same of number of electron and protons. Therefore chlorine is the element that has 17 protons. Hence the element is Chlorine.
Ans=>3] the mixture can contain more or less iron, but iron sulfide always contains equal amounts of iron and sulfur
the iron and sulfur atoms are not joined together in the mixture, but they are joined together in iron sulfide
the iron and sulfur still behave like iron and sulfur in the mixture, but iron sulfide has different properties from both iron and sulfur
you can separate the iron from the mixture using a magnet, but this does not work for iron sulfide
Ans=>4]Lead nitrate is a white crystalline solid. The material is soluble in water. It is noncombustible but it will accelerate the burning of combustible materials. If large quantities of the material are involved in the fire an explosion may result. Prolonged exposure of the material to fire or heat may result in an explosion. Toxic oxides of nitrogen are produced in fires involving this material.
Ans=>5] (sorry l can't get this question ans . in book .)
Ans=>6Chemical formula of the following is as follows:
(a) Magnesium chloride = MgCl
2
(b) Calcium oxide = CaO
(c) Copper nitrate = Cu(NO
3
)
2
(d) Aluminium chloride = AlCl
3
(e) Calcium carbonate = CaCO
3
Ans=>7] The method of representing a chemical reaction with the help of symbols and formulae of the substances involved in it is known as chemical equation. For example, zinc metal reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas.
Ans=>8] B) magnesium, copper,oxygen, calciumfloride,hydro- nitrate, barim aluminum.
(sorry I can't find ans. of a).
hope this answers are helpful to you.