Answer:
it woul be 263
Explanation:
becaue it adds up like that
Each isotope of Oxygen has a different number of neutrons
<h3>Further explanation
</h3>
The elements in nature have several types of isotopes
Atomic mass is the average atomic mass of all its isotopes
Isotopes are atoms has the same number of protons but has a different number of neutrons.
So Isotopes are elements that have the same Atomic Number (Proton)
Some of the isotopes of oxygen are:

Each isotope has 8 protons and 8 electrons but has a different number of neutrons
For O-16: number of neutrons = 16-8 = 8
For O-17: number of neutrons = 17-8 = 9
For O-18: number of neutrons = 18-8 = 10
Metal have some properties like lustrous (shiny), good conductors of electricity and heat,etc. Metals have another property by which metal can be drawn into a wire by hammering on it .This property is called as 'ductility'.
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Answer:
Extractive metallurgy
Explanation:
Extractive metallurgy is the practice of removing valuable metals from an ore and refining the extracted raw metals into a purer form.
Answer:
1. Two people stand on the same side of a large tire. Both people pull the tire with equal force.
2. an object’s ability to not change its motion
3. The car moves forward, while inertia keeps the balloon in place.
4. The unbalanced forces of air resistance and gravity slow the airplane and pull it down.
5. The force acting on the object must be unbalanced.