Elements heavier than uranium in the periodic table do not exist in any appreciable amounts in nature because they have short half-lives. Yet there are several elements below uranium in the periodic table that have equally short half-lives but do exist in appreciable amounts in nature. How can you account for this?

What region of the periodic table has the most elements? A. inert gases B. metals C. nonmetals D. semimetals

The inner transition elements
(a) are listed below the main body of the periodic table.
(b) are the p-block elements.
(c) include the noble gases.
(d) each have full f sublevels.

With the help of the Periodic Table, find the listed:
Which of the elements $\mathrm{Br}$ and $\mathrm{Ca}$ would be expected to be more acidic?

How are the electron arrangements in a given group of the periodic table related? How is this relationship manifested in the properties of the elements in the given group?

Elements in group 7 A in the periodic table are called the halogens; elements in group 6A are ca lled the chalcogens. What is the most common oxidation state of the chalcogens compared to the halogens?

Without looking at your textbook or the periodic table, name three elements in each of the following groups (families).

a. halogens

In what region of the periodic table are you likely to find elements that form more than one stable ion?

For each of the following elements, use the periodic table on the inside cover of this book to write the element’s atomic number.

d. cadmium

In his periodic table, Mendeleev placed the elements in order of increasing atomic mass. Explain why this approach is not entirely valid .

Using the periodic table only, arrange the elements in each set in order of increasing EN:
(a) S, O, Si;
(b) Mg, P, As.

Using the periodic table to guide you, predict the chemical formula and name of the compound formed by the following elements: K and S.

For each of the following elements, use the periodic table on the inside cover of this book to write the element’s atomic number.

g. V

Using the periodic table to guide you, predict the chemical formula and name of the compound formed by the following elements: Ga and F.