Answer: 6 & 8
Explanation:
I got it correct on my test hope this helped
Answer: 72 grams of
are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number
of particles.
To calculate the number of moles, we use the equation:

Putting in the values we get:


According to stoichiometry:
1 mole of
requires 5 moles of oxygen
0.45 moles of
require=
moles of oxygen
Mass of 
72 grams of
are needed to completely burn 19.7 g 
The valence electron does the halogens possess are 7
- Valence electrons are found in the outermost energy level of an atom
- They are involved in the formation of chemical bonding with other atoms.
- The halogens elements are found in group 17 on the periodic table
- The halogens include fluorine, chlorine, bromine, iodine and astatine.
- They have seven valence electrons, so they are extremely reactive as they only need one more to fill their outer shell.
- By octet rule we can say that the electron with 8 outer most shell is full and stable.
Hence the halogens posses 7 valence electron
Learn more about the valence electron on
brainly.com/question/13552988
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Answer:
18.22874999999973
I recommend you to round the nearest 1 d.p
Explanation:
<em>h</em><em>a</em><em>v</em><em>e</em><em> </em><em>a</em><em> </em><em>g</em><em>r</em><em>e</em><em>a</em><em>t</em><em> </em><em>d</em><em>a</em><em>y</em><em>!</em>
The answer is c.) Rutherford model