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  1. Mendeleev's periodic table of elements was organized by
Amass
Batomic number
Cnumber of electrons
Dnumber of protons

  1. Compared with Group 6A elements, Group 2A elements have
Amore atoms in the ground state.
Bmore valence electrons.
Cmore isotopes.
Dfewer valence electrons.

  1. Which element is found in most of the compounds in your body except for water?
Aiodine
Bpotassium
Ciron
Dcarbon

  1. Which of the following Group 1A elements is the least reactive?
ACs (cesium)
BLi (lithium)
CK (potassium)
DNa (sodium)

  1. To keep them from reacting, some highly reactive elements are stored in
Awater.
Bpure oxygen.
Cliquid mercury.
Dargon.

  1. The tendency of an element to react is closely related to
Aits atomic mass.
Battractions between its atoms.
Cthe number of valence electrons in atoms of the element.
Dthe ratio of protons to neutrons in atoms of the element.

  1. The usefulness of Mendeleev’s periodic table was confirmed by
Athe discovery of subatomic particles.
Bits immediate acceptance by other scientists.
Cthe discovery of elements with predicted properties.
Dthe discovery of the nucleus.

  1. Group 8A of the periodic table contains the
Aleast reactive metals.
Bmost reactive metals.
Cleast reactive nonmetals.
Dmost reactive nonmetals.

  1. One twelfth the mass of a carbon-12 atom is used to define a(an)
Aatomic mass unit.
Batomic mass.
Cmass number.
Datomic number.

  1. Atoms of the least reactive elements tend to have
Aone or seven valence electrons.
Beight valence electrons.
Cfour or five valence electrons.
Dno valence electrons.


Verified Answer :

transitionstate

1. Mendeleev's periodic table of elements was organized by,

Answer:

             Mass

Explanation:

                       Mendeleev was a Russian chemist who worked on periodic table after John Newland. Mandeleev arranged the elements in periodic table in order of their relative atomic masses. It was realized by Mendeleeve that most of the chemical and physical properties of elements were related to their atomic masses. Also, these properties were found to repeat after a specific periodicity hence, he arranged the elements with same properties in a vertical columns now known as groups.

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2. Compared with Group 6A elements, Group 2A elements have,

Answer:

               Fewer valence electrons.

Explanation:

                       Group 6A also known as oxygen family has a general valence shell electronic configuration as shown below,

                                                      ns², np⁴

                       While, Group 2A also known as Alkaline earth metals have a general valence shell electronic configuration as shown below,

                                                      ns²

Therefore, it is concluded that the Group 2A elements have 2 valence electrons while, 6A elements have 6 valence electrons in valence shell respectively.

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3. Which element is found in most of the compounds in your body except for water?

Answer:

               Carbon

Explanation:

                     Our body contains organic compounds. Organic compounds are those compounds which are made up of carbon atoms. Due to peculiar behavior of Carbon it has a property of Catenation (self linkage), isomerism (compounds having same molecular formula but different structural formula) and multiple bond formation (single, double and triple bonds) it results in the formation of numerous organic compounds in our body including proteins, enzymes, lipids, and much more.

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4. Which of the following Group 1A elements is the least reactive?

Answer:

               Lithium

Explanation:

                     Reaction rate of Group 1A depends upon the ionization energy of particular element. Smaller the ionization energy greater is the reactivity of that element. Hence, Lithium having the greatest ionization energy will be the least reactive and Cesium having the least ionization energy will be the most reactive element.

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5. To keep them from reacting, some highly reactive elements are stored in,

Answer:

               Argon

Explanation:

                         In order to keep them away from reacting one should keep the compounds in inert environment. In given Argon is the substance which belongs to Group of inert class of elements called as noble gases. Noble gases are least reactive because they have their valence shell complete. Hence, with complete octet noble gases are the stable elements hence least reactive.

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6. The tendency of an element to react is closely related to

Answer:

               The number of valence electrons in atoms of the element.

Explanation:

                     Atoms react with each other to form a molecule or compounds in order to gain stability. For example,

                                        2 Na  +  Cl₂    →    2 NaCl

In above reaction sodium metal losses one electron and chlorine gains one electron. Also, sodium only looses one electron because it has only one valence electron so by loosing that electron it gains a stable electronic configuration of Neon. On the other hand Chlorine has 7 valence electrons so in order to gain a noble gas configuration of Argon Cl gains one electron. Hence, we can conclude that the valence electrons are responsible for the reactivity of elements.

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7. The usefulness of Mendeleev’s periodic table was confirmed by

Answer:

               The discovery of elements with predicted properties.  

Explanation:

                      As discussed earlier Mendeleev arranged elements with same chemical properties in a vertical columns called as groups. At that time few elements were still not discovered hence their position was reserved in advanced and their properties were predicted bases on the properties of elements present in the same groups.

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8. Group 8A of the periodic table contains the

Answer:

               Least reactive nonmetals.  

Explanation:

                          Already discussed, Group 8 elements also called as noble gases are inert in nature and are least reactive in nature. The reason for least reactive nature is the complete octet. As atoms have reactivities due to loosing or gaining electron in order to gain noble gas configuration, Noble gases don't follow that trend as it already has a complete octet.


Remaining Questions are attached below.

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