Question

According to Dalton's atomic theory, all of the following are true besides:

A) All atoms of an element have the same chemical properties

B) Chemical combing of elements to form compounds involves the bonding together of different whole atoms

C) Atoms change the kind of atom they are during chemical reactions

D) New substances are produced in chemical reactions by the rearrangement of atoms

According to the octet rule, many atoms will react with each other and form compounds so that all the atoms end up with:

A) electron configurations that are identical

B) Eight electrons in their outer-most shell

C) No valence electrons

D) The same number of electrons in each of their shells

Metal atoms:

A) Lose valence electrons and form (-) ions.

B) Lose valence electrons and form (+) ions

C)Gain valence electrons and form (+) ions

D) Gain valence electrons and form (-) ions.

Nonmetal atoms:

A) Lose valence electrons and form (-) ions.

B) Lose valence electrons and form (+) ions

C)Gain valence electrons and form (+) ions

D) Gain valence electrons and form (-) ions.

Answer 1

Q.1) ans.

C) Atoms change the kind of atom they are during chemical reactions.

Dalton based his theory on the law of conservation of mass and the law of constant composition.
The first part of his theory states that all matter is made of atoms, which are indivisible.
The second part of the theory says all atoms of a given element are identical in mass and properties.
The third part says compounds are combinations of two or more different types of atoms.
The fourth part of the theory states that a chemical reaction is a rearrangement of atoms.
Parts of the theory had to be modified based on the discovery of subatomic particles and isotopes.

Q.2) ans.

B) Eight electrons in their outer-most shell.

The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell. When atoms have fewer than eight electrons, they tend to react and form more stable compounds.

Q.3) ans.

B) Lose valence electrons and form (+) ions.

Atoms that lose electrons acquire a positive charge as a result because they are left with fewer negatively charged electrons to balance the positive charges of the protons in the nucleus. Positively charged ions are called cations.

A neutral sodium atom is likely to achieve an octet in its outermost shell by losing its one valence electron.

Na →Na+ + e−

The cation produced in this way, Na⁺, is called the sodium ion to distinguish it from the element.

Q.4) ans.

D) Gain valence electrons and form (-) ions.

Nonmetals like to gain electrons to form anions to have a fully stable octet. They release energy (exothermic) to gain electrons to form an anion; thus, electron affinity of nonmetals is higher than that of metals. ​