Периодическая система химических Элементов

Что объединяет эти изображения?

4.2 The Periodic Table

Learning Goal Use the periodic table to identify the group and the period of an element; identify the element as
a metal, a nonmetal, or a metalloid.

© 2014 Pearson Education, Inc.

In 1872, Dmitri Mendeleev
created the periodic table
arranged elements by increasing atomic mass
arranged elements into groups with similar properties

© 2014 Pearson Education, Inc.

5

On the periodic table
elements are arranged according to similar properties in vertical columns called groups
periods are horizontal rows of elements
Periods 1 contains two elements: H and He
Periods 2 and 3 each contain eight elements:
Periods 2 – Li, Be, B, C, N, O, F, Ne Periods 3 – Na, Mg, Al, Si, P, S, Cl, Ar

Group Numbers, written at the top of each vertical column, are written two ways:
The letter A is used for the representative elements 1A to 8A and the letter B for the transition elements.
The numbers 1–18 are used for the columns from left to right.

Representative elements include
Group 1A (1), called Alkali metals
Li, Na, K, Rb, Cs, and Fr
Group 2A (2) called Alkaline earth metals
Be, Mg, Ca, Sr, Ba, and Ra
Groups 3A (13), 4A (14), 5A (15), and 6A (16)
Group 7A (17), called Halogens
F, Cl, Br, I, and At
Group 8A (18), called Noble gases
He, Ne, Ar, Kr, Xe, and Rn

Group 1A (1) Group 7A (17)
Alkali metals Halogens

Lithium 1Li2, sodium
1Na2, and potassium 1K2 are some
alkali metals from Group 1A 112.

Chlorine 1Cl22, bromine
1Br22, and iodine 1l22 are
halogens from Group 7A 1172.

The heavy zigzag line on the periodic table separates the metals from nonmetals. Metalloids border the zigzag line.

Most metals are shiny solids, such as copper (Cu), gold (Au), and silver (Ag).
Metals are
ductile, can be shaped into wires
malleable, can be hammered into a flat sheet
good conductors of electricity
melted at much higher temperatures than nonmetals
solids at room temperature, except for mercury (Hg)

Except for aluminum (Al), the elements along the zigzag line are metalloids. Metalloids
include B, Si, Ge, As, Sb, Te, Po, and At
exhibit some properties typical of metals and some typical of nonmetals
are better conductors of heat and electricity than nonmetals, but not as good as metals
are semiconductors because they can be modified to function as conductors or insulators

Nonmetals include elements such as hydrogen (H), carbon (C), nitrogen (N), oxygen (O), chlorine (Cl), and sulfur (S).
Nonmetals
not especially shiny, malleable, or ductile, and are often poor conductors
of heat and electricity
typically have low melting
points and low densities

Only 20 elements are essential for the well-being and survival of the human body.
Only four elements, oxygen (O), carbon (C), hydrogen (H) and nitrogen (N) make up 96 % of our body mass.
The macrominerals Ca, P, K, Cl, S, Na, and Mg are involved in the formation of bones and teeth, and the maintenance of essential body functions.

Match the elements to the description:
A. Metals in Group 4A (14)
(1) Sn, Pb (2) C, Si (3) C, Si, Ge, Sn

B. Nonmetals in Group 5A (15)
(1) As, Sb, Bi (2) N, P (3) N, P, As, Sb

C. Metalloids in Group 4A (14)
(1) C, Si, Ge (2) Si, Ge (3) Si, Ge, Sn, Pb

Match the elements to the description:
A. Metals in Group 4A (14)
(1) Sn, Pb

B. Nonmetals in Group 5A (15)
(2) N, P

C. Metalloids in Group 4A (14)
(2) Si, Ge