Internal validity has to do with the accuracy of the results. Results could be inaccurate if samples are not selected randomly. External validity has to do with the generalizability of the findings to the population. If the sample selected is only hispanics under the age of 25, then it would be hard to generalize the results to the entire US population.
What is the make up of an atom?
Atoms are made up of protons, neutrons, and electrons. The protons and neutrons are found together in the core of the atom, called the nucleus, which is in the center. The electrons are found moving around the nucleus (at different energy levels) in what is called the electron cloud.
What is the atomic number?
The atomic number of an element is equal to the number of protons in the nucleus of an atom of the element. Protons are positively charged particles found in the center of every atom
What is the atomic mass?
The sum of protons and neutrons in an atom
atoms share valence electrons
nonpolar covalent=h2 o2
valence electrons are transfered from one atom to another