Indicate the number of protons, neutrons, and electrons in each of these species: $${ }_{7}^{15} \mathrm{~N},{ }_{16}^{33} \mathrm{~S},{ }_{29}^{63} \mathrm{Cu},{ }_{38}^{84} \mathrm{Sr},{ }_{56}^{130} \mathrm{Ba},{ }_{74}^{186} \mathrm{~W},{ }_{80}^{202} \mathrm{Hg}$$

The atomic number is a fundamental property of an element and represents the number of protons found in the nucleus of an atom. It's essentially the fingerprint of an element, as no two elements have the same atomic number. In symbols like \( _{7}^{15} \mathrm{N} \), the lower number (7) is the atomic number.

Understanding the atomic number is crucial because it not just identifies the element but also gives us the number of electrons in a neutral atom. For example, nitrogen has an atomic number of 7, so it has 7 protons and, in its neutral state, 7 electrons. Let's remember, the electrons are the negatively charged particles that orbit the nucleus and define most of the chemical properties of an atom.

For aspiring chemists, a solid grasp on the concept of atomic numbers paves the way for learning about the periodic table, where elements are ordered by their atomic numbers.

If the atomic number is the identity of an element, think of the atomic mass number as its weight ticket. The atomic mass number tells you the total number of protons and neutrons in an atom's nucleus. For instance, \( _{29}^{63} \mathrm{Cu} \) indicates copper with an atomic mass number of 63. This number is always at the top and is typically larger than the atomic number.

Calculating the number of neutrons is a cinch when you have the atomic mass number and the atomic number: subtract the atomic number from the atomic mass number. So for copper-63, with 29 protons (atomic number), and a mass number of 63, there are 63 - 29 = 34 neutrons. Neutrons are the neutral counterpart to protons, adding to the mass but not affecting the charge of the atom.

This concept helps you understand isotopes—variations of the same element with different numbers of neutrons leading to different mass numbers, which is important when studying radioactive materials or doing isotopic dating.

Atoms are constructed from three main particles: protons, neutrons, and electrons. Protons carry a positive charge and reside in the nucleus. Neutrons also live in the nucleus but have no charge. This duo makes up the atom's mass. Outside the nucleus, electrons with their negative charge whizz around and balance the positive charge of protons in a neutral atom.

For example, Mercury (\( _{80}^{202} \mathrm{Hg} \) ), identified by the atomic number 80, has 80 protons and electrons, and by subtracting the atomic number from the atomic mass number, 202 - 80 = 122 neutrons. The organization of these particles determines the atom's identity, its mass, and how it will interact with other atoms chemically.

To fully appreciate the dance of chemistry, understanding the interplay of protons, neutrons, and electrons is key. These basics of atomic structure are the building blocks for more advanced topics like chemical bonding, the periodic trends in the periodic table, and the behavior of materials at the molecular level.