If your question is of the core of the Earth, it is suspected to be made of iron and nickel.
<em>Answer:</em>
<em>Ello mate ! the answer is super simple it's option "A" Fe</em>
<em>Explanation:</em>
<em>Iron is a chemical element with symbol</em><em> "Fe"</em><em> and atomic number 26. It is a type of metal, that belongs to the first transition series and group 8 of the periodic table. It is by mass the most common element on Earth, forming much of Earth's outer and inner core.</em>
Answer:
The symbol for an atom can be written to show its mass number at the top, and its atomic number at the bottom. To calculate the numbers of subatomic particles in an atom, use its atomic number and mass number: number of protons = atomic number. number of electrons = atomic number.
Answer:
The half-life of a radioisotope describes the amount of time it takes for said isotope to decay to one-half the original amount present in the sample.
Nitrogen-13, because it has a half-life of ten minutes, will experience two half-lives over the course of the twenty minute period. This means that 25% of the isotope will remain after this.
0.25 x 128mg = 32mg
32mg of Nitrogen-13 will remain after 20 minutes.
