The correct option is C.
An atom can be either in the ground state or in an excited state. An atom is said to be in the ground state, if the total energy of its electron can not be lowered by moving one or more electrons into different orbitals. At the ground state, the electrons in the atom have the lowest energy possible and they are stable. On the other hand, an atom is said to be in an excited state, if the energy of its electrons can be lowered by transferring one or more electrons into different orbitals. An atom in an excited state has more energy and is less stable.
The bond that exist between two oxygen atoms is
called a double covalent bond. This bond involves the sharing of four electrons
to obtain a more stable structure. This type of bond is much stronger than the
single covalent bond. They are much harder to break.
Answer:
Fossils are the some traces or portions of the animals or plants, buried and preserved from past in rocks, sediments or ice.
Explanation:
Correct match is as follows-
- Mold and cast fossils- An organism is buried in sediment after it dies.The hard part of organism leave behind a empty space imprinted in the rock. Later sediments and minerals fill the space and harden to make the original copy of the organisms.
- Carbon film fossils- An organism buried in sediments gets squeezed and heated inside the earth , leaving behind a thin carbon outline of the organism on a rock.
- Amber fossil- An organism covered in tree resin or tree sap , which then hardens with the body of the organisms preserved inside.
- Ice fossil- An organism dies in a cold place on earth , its body becomes frozen and covered in layers of ice . The hard and soft part of the body may be preserved.
If you are talking about bonds they are influenced by electronegativity and how many valence electrons they have.
Explanation:
Before proceeding, let's understand what thermosphere and mesosphere are;
The mesosphere is the third layer of the atmosphere, directly above the stratosphere and directly below the thermosphere.
The thermosphere is the layer in the Earth's atmosphere directly above the mesosphere and below the exosphere.
The meteors make it through the exosphere and thermosphere without much trouble because those layers don't have much air. But when they hit the mesosphere, there are enough gases to cause friction and create heat.
Temperatures in the mesosphere decrease with altitude. Because there are few gas molecules in the mesosphere to absorb the Sun's radiation, the
heat source is the stratosphere below. The mesosphere is extremely cold.
Satellites and the International Space Station orbit the Earth within the thermosphere.
Mesosphere;
- is directly above the stratosphere
- acts as a barrier to meteoroids
- is very cold
Thermosphere;
- reaches out into space
- is where satellites travel
