The answer to this question would be: 3.125%
Half-life is the time needed for a radioactive molecule to decay half of its mass. In this case, the strontium-89 is already gone past 5 half lives. Then, the percentage of the mass left after 5 half-lives should be:
100%*(1/2^5)= 100%/32=3..125%
Answer:
The answer remains the same. The total amount of energy stays the same because the 1st Law of Thermodynamics states that energy can neither be created nor destroyed, it can only change forms. So the chemical energy is just being converted into heat and light.
Explanation:
hope this helps...
Answer:
They have properties of both metals and nonmetals
Explanation:
- Elements in the periodic table may be divided into Metals, non-metals, and metalloids.
- Metals are the elements that react by losing electrons to form stable positively charged ions known as cations. Examples are group 1, 2, and 3 elements together with transition elements.
- Non-metals are those elements that react by gaining electrons to form stable negatively charged ions called anions. Examples include oxygen, carbon, sulfur, etc.
- Metalloids, on the other hand, are elements that have both metallic and non-metallic properties.
- Metalloids occur between metals and non-metals in the periodic table. Examples include Boron and silicon among others.
The element symbol in chemistry comprises atomic number and mass number.
Atomic number is written on the top of element and mass number is written at the bottom.
For eg:
If Y is an element that is having atomic number a and mass number x. Then its denotion will be:
ᵃYₓ.
So here ⁹F₁₈.₉₉
Here 18.99 will denote mass number while 9 will denote atomic number.
