Answers
1. 8 electrons
2. 10 electrons
3. 10 electrons
4. 8 from the oxygen atom and 1 from each of the 2 hydrogen atoms
5. 4 hydrogen bonds
Explanation
The atomic number of oxygen is 8 thus it has a total of 8 electrons. When writing the electron configuration for the oxygen, the first n shell requires two electrons to complete the 1st orbital. The fact that 1s holds a maximum of 2 electrons the next 2 electrons of oxygen goes to 2s orbital. The 2s orbital takes a maximum of two electrons and the remaining 4 electrons occupy the 2p orbital. The configuration formed will be 1s² 2s² 2p4 .The maximum number of electrons in the second shell is 2n²=2×2² =8 from the formula 2n² (the maximum number of electrons in a shell). The total number of electrons in the second shell is 2(in s orbital) +4 (in p orbital) =6.The number of unpaired electrons is 8-6=2
A water molecule has four hydrogen bonds, because it is made up of two hydrogen atoms and an oxygen atom. A water molecule has 10 protons and 10 electrons thus it is neutral. In the water molecule there is formation of covalent bonds where oxygen atom and hydrogen atoms share electrons though the sharing is not equal. In the covalent bond, the oxygen atoms attract electrons more than the hydrogen atoms.
The various components of an arthropod's nervous system are:
A dorsal brain present at the head end
A bundle of nerves which helps in coordination of movements and sensory actions.
Ventral nerve cords are resent from the brain to the rear end.
Two cords are joined by parallel commissures.
They also have segmental ganglia, and subesophagal ganglia.
The answer is B. The reason why is because natural selection causes changes in a populations over many generations, and in this case the change that is being made is the that the population is becoming immune to a disease.
I think its false because you gain energy over the time you lose and have.
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