Answer:
A. Non-metal
B. Six
C. 2
D.NA2O
E.Oxygen
Explanation:
Oxygen is the element in the second period (second horizontal row) and Group VI A of the periodic table. These properties apply to oxygen
Answer : The diatomic molecule of chlorine, Cl₂, is held together by a SINGLE covalent bond.
Covalent Bond :
It is type of chemical bond, which is formed by sharing of electron between atoms . The covalent bond is formed between two non metals . The valance electron are shared to form the bond . The shared electrons are known as BONDING electron pair and the electron pair which do not take part in bonding are known as NON- BONDING electron pair. Example : O₂ , H₂ , H₂O, NH₃ etc .
Formation of covalent bond in Cl₂ :
Chlorine is present in group 17 in p block , It is a non metal .
The electronic configuration of Cl is : 1s² 2s² 2p⁶ 3s² 3p⁵ .
Since the outer shell is n= 3 , which has 7 electrons in it , hence Cl has 7 valence electrons in it .
From electronic configuration , it can be seen that Cl need 1 electron to complete its octet (3s² 3p⁶ ). Hence when two Cl atoms come close they share one-one electron with each other (as shown in image ) .
Now the octet of both the atom are complete and they are in stable state together .
When both Cl atom share one e⁻ , there is a bond formed between Cl atoms . One bond consists of 2⁻ . Hence in Cl₂ SINGLE covalent bond present .
Cl + Cl -> Cl₂
<span>The Law of Conservation of Mass simply states
that the total amount of mass should not change in a chemical reaction that is
isolated (no other objects can enter the reaction). The total mass of the
reactants must be equal to the total mass of the products. Thus, t</span>he correct estimate of
the amount of oxygen used in the interaction is the difference between 133
g and 29 g.
<u>Full question:</u>
When energy is changed from one form to another, some of the energy is lost to the surroundings as waste thermal energy. The more steps needed to arrive at the desired energy or the more types of energy that are generated, the more energy is wasted.
Which object would likely have the least amount of wasted energy?
A) an electric drill
B) a solar cell
C) a car engine
D) a hydroelectric dam
Solar cell
<u>Explanation:</u>
In an electric drill, the conversion of electrical energy into mechanical energy takes place. Heat energy is obtained when the desired object gets broken with the drill.
In car engine, thermal energy is obtained from the chemical energy which in turn is converted into mechanical energy which is very essential for moving car.
In hydroelectric dam, energy is obtained from water that is stored in dam. The potential energy of water is transformed into mechanical energy which in turn is converted into kinetic energy which again is transformed into an electrical energy.
In the above methods the transformation of energy takes many steps wherein more amount of energy gets wasted.
In Solar cell, the energy that is obtained from the sun is directly converted into electrical energy. Hence, in solar cell, only less amount of energy will be wasted.
<span>It contains all necessary parts of an atom, but the energy levels are portrayed incorrectly</span>
