Answer:

Explanation:
The question is asking to write the <em>isotopic symbol </em>of the form
for the <em>sodium isotope with 13 neutrons</em>.
In general, the isotopic symbol in the given form shows:
- The element's chemical symbol: X
- A: mass number of the isotope, written as a superscript to the left of the element's simbol, and
A = number of protons + number of neutrons
- Z: atomic number of the isotope, written as a subscript to the left of the elements's symbol,
Z = number of protons
The atomic symbol of sodium is Na.
The atomic number, or number of protons, is the same for every isotope of the element, and you can find it in any periodic table. Tha atomic number of sodium is 11. Thus:
The mass number is the number of protons plus neutrons, hence:
Now you can write the isotope symbol for the sodium isotope with 13 neutrons:

Answer:
A team of Chinese researchers have turned cheap copper into a new material “almost identical” to gold, according to a study published in peer-reviewed journal Science Advances on Saturday. The fast-moving ionized particles blasted copper atoms off the target.
hope this helps
have a good day :)
Explanation:
The apparent topography exhibited by minerals in thin section as a consequence of refractive index.
Answer:
Summary. To summarize, the periodic table is important because it is organized to provide a great deal of information about elements and how they relate to one another in one easy-to-use reference. The table can be used to predict the properties of elements, even those that have not yet been discovered.