Answer:
The corona shines only about half as brightly as the Moon and is normally not visible to the unaided eye, because its light is overwhelmed by the brilliance of the solar surface. During a total solar eclipse, however, the Moon blocks out the light from the photosphere, permitting eye observations of the corona.
Answer:
Explanation:
(a) Firstly, caesium abd potassium are both in Group 1 of the periodic table. Group 1 metals (also called alkali metals) are the most reactive metals of the periodic table. Caesium is more reactive than Potassium because it has a higher electropositivity than Potassium. Electropositivity is the tendency of a metal to donate electron(s) to form a cation. Electropositivity increases down the group; this is because it is easier for atoms to loose electrons on the outermost shell that are far away from the central nucleus as against atoms whose outermost electrons are closer to the central nucleus. <u>Thus, the more "bulky" an atom is, the farther it's outermost electrons (valence electrons) get from the central nucleus and the easier it is to lose the outermost electron(s). And the easier it is for the valence electron(s) to be removed, the more reactive the atom would be and vice-versa.</u>
Caesium is more reactive than potassium because it is more bulky than potassium, with an atomic number of 55, while potassium has an atomic number of 19.
NOTE: The closer an electron is to the nucleus, the more difficult it is to be removed from it's shell.
(b) i. Formula for Caesium Nitrate:
Symbol for Caesium is Cs and Nitrate is NO₃⁻.
Cs⁺ + NO₃⁻ ↔ CsNO₃
Formula for Caesium Nitrate is CsNO₃
ii. Formula for Caesium sulphate
Symbol for caesium is Cs and Sulphate is SO₄²⁻
Cs⁺ + SO₄²⁻ ↔ Cs₂SO₄
Formula for Caesium sulphate is Cs₂SO₄
NOTE: When writing the formulae, the charges would be exchanged to form the subscript as seen on the product sides above.
Answer:
Option B is correct.
4
Explanation:
We know that an atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example, if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.
In given problem we are given with 2 neutrons of helium. We know that the atomic number of He is 2. Thus Mass number of He is,
Number of neutrons + number of proton
2 + 2 = 4
Thus, option B is correct.
Answer:
Kinetic Energy
Explanation:
Kinetic energy is the energy inside moving objects of things.
