Write isotopic symbols in the form X to A (example C-13) for each isotope. a. the silver isotope with 60 neutrons b. the silver isotope with 62 neutrons c. the uranium isotope with 146 neutrons d. the hydrogen isotope with 1 neutron

The atomic number is fundamental to the identity of an element. It is designated by the letter Z and represents the number of protons in the nucleus of an atom. Protons are positively charged particles, and because atoms are electrically neutral overall, the atomic number also tells us the number of electrons in an uncharged atom. For example, hydrogen, which is the lightest element, has an atomic number of 1, meaning it has one proton (and one electron in its neutral state). In the exercise, knowing that silver has an atomic number of 47 allowed us to understand that every silver atom has 47 protons in its nucleus, regardless of the isotope.

Understanding atomic number is crucial because it defines the chemical properties of the element and its placement in the periodic table. It's important to note that elements are ordered in the periodic table by their atomic number, not by their mass numbers.

The mass number, represented by the letter A, is the sum total of protons and neutrons in an atom's nucleus. Unlike the atomic number, the mass number is not found on the periodic table because it can vary for each element based on the number of neutrons. Neutrons add to the mass of the atom but do not affect its chemical properties. So, to find an element’s mass number in isotopes, one simply adds the number of protons (atomic number) to the number of neutrons.

For instance, in the silver isotope with 60 neutrons, the mass number was calculated as 107 by adding the atomic number of silver (47) and the number of neutrons (60). This mass number is critical when writing isotopic symbols and particularly useful when distinguishing between different isotopes of the same element.

Isotopes are variations of the same chemical element that have different numbers of neutrons. While the number of protons (and hence the atomic number) remains constant across isotopes of an element, the number of neutrons can vary, leading to different mass numbers. This variation in neutrons affects the mass and sometimes the stability of the isotope.

In our exercise, we looked at different isotopes of silver and uranium. The silver isotope with 60 neutrons is Ag-107, and with 62 neutrons is Ag-109. Uranium's isotope with 146 neutrons was U-238. It's this difference in neutron count that makes each isotope unique, and knowing how to calculate the number of neutrons is essential – you subtract the atomic number from the mass number (\( A - Z = \text{number of neutrons} \)).

Chemical element symbols are shorthand notations of the elements based on their names, usually derived from their Latin names. Each symbol consists of one or two letters, with the first letter always capitalized. For example, the symbol for hydrogen is 'H', for silver it is 'Ag' (from its Latin name 'Argentum'), and for uranium, it is 'U'.

Element symbols make it easier to write and communicate chemical information. When combined with mass numbers, we get isotopic symbols – these not only tell us the element but also the specific isotope. So, 'Ag-107' refers to the silver isotope with 107 as its mass number, which, as we learned, indicates a specific combination of protons and neutrons unique to that isotope.