Answer:
validity is the extent to which a test measures what it claims to measure. It is vital for a test to be valid in order for the results to be accurately applied and interpreted.
Explanation:
Validity is important because it can help determine what types of tests to use, and help to make sure researchers are using methods that are not only ethical, and cost-effective, but also a method that truly measures the idea or constructs in question.
The correct answer is option C, 2.5
lithium and potassium are both in the alkali family and they are metals. Fluorine is a non-metal and lives in the halogens family. But, each of them have 2 valence electrons in the innermost ring
The mass number = protons + electrons
Atomic number= protons (and electrons)
You can determine the number of neutrons by subtracting the number of protons from the mass number
