When the number of protons and electrons are equal, that means the element is neutral. So, to know the element, find the element with an atomic number of 10. That would be Neon. Next, solve the mass number.
Mass number = protons +neutrons = 10+11 = 21
Thus, the expression should be written as shown in the attached picture.
The amount of Silicon left after 300 years is 75g
It is given that the initial amount of Si is 100 times decay is 300 years and the half-life of Silicon is 710 years.
The radioactive decay formula is given by,
A = A₀ x 2^(-t/h);
where;
A is the resulting amount after t time, Ao is the initial amt (t=0),t is the time of decay, and h is the half-life of the substance.
On substituting the values from the given we get,
A = 100x2^(-300/710)
A = 100 x 0.746112347
A = 74.6112347 grams left after 300 yrs
Therefore, the number of grams of silicon left after 300 years is 74.6112347g. This value could be rounded off to 75 grams as in the whole number
To know more about half-life, click below:
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Answer:
Formation of Gas
Explanation:
The solid Carbon Dioxide warms it sublimates to gas. With limited room for the gas to expand, the pressure in the bottle increases.
Galileo was the first scientist to measure speed as distance over time.
A force or a type of friction?
Force: Resistance--> If you go swimming, you feel the water pushing against you, making it harder to walk in water and even to swim unless you are doggy pattling or front strokes. Resistance is a force going against a solid object.
Friction: Fluid friction which is friction that occurs after a solid object travels through a liquid or gas
