Answer:
Measuring distances to stars through stellar parallax. Measuring distances to stars through the moving cluster method. Astronomers measure the temperature of a star by looking at the star's color and its spectrum. The apparent brightness of a star tells how bright it seems to us
Explanation:
Answer:
Answer: (b) F
Explanation:
Sodium has 1, magnesium has 2 and Aluminium has 3 electrons in its outermost shell whereas Fluorine has 7 electrons in its outermost shell hence Fluorine does not lose electrons easily.
The electronic configuration of fluorine is 2,7.
Fluorine is the ninth element with a total of 9 electrons.
The first two electrons will go in the 1s orbital.
The next 2 electrons for F go in the 2s orbital.
The remaining five electrons will go in the 2p orbital. Therefore the F electron configuration will be 1s22s22p5.
Answer:
2.19 x 10^-12.
Explanation:-
The relation between Ka and Kb for an acid and it's conjugate base is
Ka x Kb = Kw where Kw = ionic product of water.
So Kb = 10^-14 / (4.57 x 10 ^ -3)
= 2.19 x 10^-12
Number of proton present in the nucleus determines the atomic number of an element. It determines <span>chemical properties, which is why all atoms with proton count (atomic number) 6 are carbon</span>
