Answer:
3. An oxygen atom with 8 electrons, 8 protons, and 9 neutrons .
Explanation:
if an atom contains equal numbers of protons and electrons, the atom is described as being neutral.
The atomic number tells you the number of electrons. That means there are 18 electrons in an argon atom.
Answer:
Rule 1: Drop mono for the first element. Rule 2: Drop all prefixes if the first element is H. Rule 3: Drop the second o in mono prior to a vowel. Rule 4: Drop the a in prefixes ending in a prior to a vowel.
K, ca, sc is the right answer. Take a look at table S of your chemistry reference table.