All the statement is true about the elements of group 16.
In periodic table 18 vertical column are present which is called groups which are arranged from left to right in the periodic table.
In periodic table 7 horizontal rows are present which is called periods.
Now lets check all options one by one.
Option (A): They need two electrons to complete their octet.
In periodic table Group sixteen have 6 elements in its valence shell. Group 16 elements needed two electrons to complete the octet valency. The valency of group 16 elements is 2. So it is true about the group 16 elements.
Hence, it is incorrect option.
Option (B): They have an oxidation number of 2-
Group 16 show variable oxidation state that is -2, +2, +4 and +6. So the statement is true.
Hence it is incorrect option.
Option (C): They have an oxidation number of 2+.
Group 16 show variable oxidation state that is -2, +2, +4 and +6. So the statement is true.
Hence it is incorrect option.
Option (D): They have six valence electrons
Group 16 elements are called Chalcogens. They have 6 valence electron so they achieve noble gas configuration. So it is true statement.
Hence, it is incorrect option.
Thus, from the above conclusion we can say that all the statement is true about the elements of group 16.
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2. Ba2SO4
3. BaSO4
4. Ba(SO4)2
Answer:
3. BaSO4
Explanation:
the math will show you, and to answer your commented question "How does this evidence indicate that the reaction has occurred between ions ?" :
The reaction of the ions can be checked by a number of methods. In a chemical reaction, the ions are in the aqueous solution. This means that they are in solution, dissolved with charge. During the reaction (ionic) there is an attraction between the positive and negative ions. This makes a change in the state of the reactants in the products. In addition, the reaction can result in an immediate observable change such as the formation of a solid or precipitation.
b. a substance that's composed of atoms
c. the force that holds together the elements in a compound
d. the attraction of two atoms that holds the atoms togethe?
Answer: -
A chemical bond is
C) the force that holds together the elements in a compound.
Explanation: -
A chemical bond results when there is a transfer of electrons from 1 element to another or there is a sharing of electrons between two element atoms.
Due to this compounds are formed.
Hence A chemical bond is
C) the force that holds together the elements in a compound.
the correct answer should be c.
The balanced equation is: 2Fe + 3F2 ⇒ 2FeF3
A chemical equation needs to be balanced if you want to make the wide variety of the atoms of the reactants equal to the variety of the atoms of the goods.
Given,
Iron + fluorine ⇒ Iron Flouride
Fe + F2 ⇒ FeF3
Now to balance this reaction:
2Fe + 3F2 ⇒ 2FeF3
This reaction is balanced.
This medicine is a mixture manufactured from nutrients, iron, and fluoride. it's miles utilized in infants and youngsters to deal with or prevent deficiency because of terrible weight loss programs or low tiers of fluoride in drinking water and other sources.
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Answer:
iron+flourine.............iron flouride
Fe+F2.............FeF3
the above reaction is not balanced
now to balance this reaction
2Fe+3F2...........2FeF3
now this reaction is balanced