Which of the following is not a derived unit?
a) b) g/ml c)kg

c) kg

Explanation:

Kilograms stands alone. It has to be hooked up to another unit for it to be a derived unit.

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The answer to your question is c) kg

Explanation:

Derived units is when to units are combined to get a new one, For example, combining length and length gives lenght² and then we measured area, this is a derived unit.

a) cm³ this answer is wrong because we are combining length x length x length so we get the units of volume, this is a derived unit.

b) g/mL this answer is wrong because we are combining mass and volume so we can measure density, this units are derived.

c)kg this answer is correct because it measures mass and only that, then it's a fundamental unit.

not clear

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.