I believe it is DNA: deoxyribonucleic acid
The number is 
.
<u>Explanation:</u>
We have , Four times the sum of a number and -3 is 4 more than times the number.Let's consider step by step as :
Let the number be x , Four times sum of a number & -3 is 
. Now, this is 4 more than times the number i.e 
. According to question these both statements are equivalent as :
⇒
⇒ 
⇒ 
⇒
Answer:
......answer is above ......
Answer:
B
Explanation:
For metals, the further away the valence electrons are from the nucleus, the higher the reactivity of the elements. Unlike halogens that are more reactive if the valence orbital shells are closer to the nucleus. This is due to ionization energies – which is the minimum energy required to discharge an electron from its orbit.
For metals this should be lower because they need to lose electrons to attain a stable electron configuration. For halogens it should be high because they don't need to lose electrons, but rather gain, in order to attain stable electron configuration.
Electrons in their orbital shells need to occur in pairs (with opposite quantum states) to be in stable configuration and as long as an atom has orbitals with single electrons, the atoms will be reactive as opposed to when its orbitals are ‘full’.
