<h3>Explanation</h3>
Astatine has atomic number 85. "217" is the mass number of this isotope of At.
The mass number of an atom decreases by 4 as it undergoes alpha decay. Its atomic number decreases by 2. It emits an <em>alpha particle</em>, which is a helium-4 nucleus, in this process. The alpha particle has mass number 4 and atomic number 2.
The <em>daughter</em> nucleus has mass number 217 - 4 = 213 and atomic number 85 - 2 = 83. The atomic number of 83 corresponds to bismuth. Therefore the daughter nucleus is an atom of bismuth-213.
By convention, write the mass number A on the top-left corner of an element. Write its atomic number Z on the bottom-left corner. Note that A is always greater than Z for an isotope.
Answer:
it depends on the medium and the temperature
Explanation:
The answer i think it is... is Temperature
Hope this helped!
The answer should be 0.78
Both a particle and a wave?