4.2 The Periodic Table

• Write the correct elements from the symbol to the name of the element.

• The periodic table can be used to identify the group and the period of an element.

• By the late 1800s, scientists realized that elements looked the same.
• In 1869, a Russian chemist arranged the 60 elements into groups with similar properties and placed them in order of increasing atomic mass.

• The elements are arranged in groups and periods in rows on the periodic table.

• The groups going left to right across the periodic table are assigned numbers 1 to 18.

• There are 18 elements in Cs with rubidium.
• There are 32 elements in the sixth period.
• The seventh period has a total of 118 elements.

• Some groups on the table have the same names.

• There are several groups in the periodic table.

• The soft, shiny metals within this group are good conductors of heat and electricity and have relatively low melting points.
• Alkali metals form white products when they combine with oxygen.

• Although hydrogen is at the top of Group 1A (1), it is not an alkali metal and has very different properties than the rest of the elements.
• The alkali metals do not include hydrogen.

• They include elements such as magnesium, calcium, strontium, and radium.

• They are from Group 7A.

• They include He, neon,Ar, krypton, xenon, and Rn.
• They are unreactive and rarely found in combination with other elements.

• The metals can be shaped into wires or hammered into a flat sheet.

• Good conductors of heat and electricity are metals.

• Hydrogen, carbon, nitrogen, oxygen, Ge As chlorine, and sulfur are examples of nonmetals.

• The metals Po At are typical of the nonmetals.

• Sulfur is a nonmetal.

• Na, Group 1A (1), Period 3, is an alkali metal.

• Si is a metalloid.

• Only 20 elements are essential for the well-being and in lower amounts than the major elements, so that smaller amounts are survival of the human body.
• Oxygen, carbon, and other elements are required in our daily diet.

• Mo and I are maintained in Period 5 by most of the food in our daily diet.
• The human body is very small and healthy.
• Some elements are found in less than 100 calories.
• Most of the hydrogen and oxygen is found in water, which small amounts has improved so that researchers can more easily find it.

• Period 3 and Period 4 of the periodic table are still used because of the high levels of toxic elements in the body.
• The required by the body is what they are involved in.
• Formation of bones and teeth, maintenance of heart and blood vessels, and other elements, such as tin and nickel, are thought to be essential, but their role has not yet been determined.

• The amounts present in a 60 kilogram person are listed.

• If you want to identify the elements as metal, nonmetal, or a metalloid, you have to identify them.