the characteristics of the periodic table we can find the answer to identify and classify  the chemical elements
The periodic table is a way of ordering the chemical elements by their atomic number, it is made up of rows called periods and columns called groups.
The rows start in an element with one electron in its last shell and end in an element with 8 electrons in the last shell.
The column all elements have the same number of electrons in the same shell.
Let's answer each part separately
First part
Find the melting point and the state of matter
Element       melting point (ºC)    state of matter
Potassium (K) Â Â Â Â Â 63.7 Â Â Â Â Â Â Â Â Â Â Â Â Â gaseous
Iodine (I) Â Â Â Â Â Â Â Â Â 111.7 Â Â Â Â Â Â Â Â Â Â Â Â Â solid
Gold (Au) Â Â Â Â Â Â Â 1063 Â Â Â Â Â Â Â Â Â Â Â Â Â Â solid
Germanium (Ge) Â Â 937.4 Â Â Â Â Â Â Â Â Â Â Â Â solid
Barium (Ba) Â Â Â Â Â Â 714 Â Â Â Â Â Â Â Â Â Â Â Â Â Â solid
Argon           -180.4              gas
Chlorine         -101                gas
Rubidium (Rb) Â Â Â Â 38.9 Â Â Â Â Â Â Â Â Â Â Â Â Â solid
Silver (Ag) Â Â Â Â Â Â 960.8 Â Â Â Â Â Â Â Â Â Â Â Â Â solid
Calcium (Ca) Â Â Â Â 838 Â Â Â Â Â Â Â Â Â Â Â Â Â Â solid
Silicon (Si) Â Â Â Â Â Â 1410 Â Â Â Â Â Â Â Â Â Â Â Â Â Â solid
Xenos (Xe) Â Â Â Â Â Â -111.9 Â Â Â Â Â Â Â Â Â Â Â Â Â gas
2nd part
Write the missing elements, we use the periodic table and we place the elements by their row and column, that is, period and group.
The name and symbol of the missing elements are written in the following table
   1            2         11         14       17       18
1 Hydrogen    Helium
    H        He  Â
2 Lithium   Beryllium               Carbon  Fluorine   Neon
    Li         Be                  C        F      Ne
3 sodium   Magnesium             Silicon    Cl        Ar
    Na         Mg                Si
4 K             Ca       copper   Ge    Bromine    Kripton
    K         Ca                 Ge     Br         Kr
5 Rubidium  Strontium     Ag        Tin    Iodine      Xenon
   Rb      Sr           Ag        Sn      I           Xe
6 Cesium    Ba           Au        Lead    Astate     Radon
    Cs     Ba           Au          Pb      At        Rn Â
3rd part
It is requested to identify the elements by their properties.
For identification we will use the properties in the following order
Element 1
[tex]T_m[/tex] = -157 K
matter state: gas
corresponds to the  element:   Krypton
Element 2
T_m = 777ºC
State of matter: solid
conductivity: good
Corresponds to the element: Strontium
Element 3
T_m = 327º
Solid state
Corresponds to elements: Lead
Element 4
T_m = -7ºC
Liquid state
Corresponds to Bromine
Element 5
T_m = 1085ºC
conductivity: excellent
Corresponds to the element  Copper Â
Element 6
T_m = 29ºC
Solubility: reacts violently
Corresponds to the element Cesium
Â
In conclusion, using the characteristics of the periodic table, we can find the answer to identify and calcify the chemical elements.
Learn more about the periodic table here:
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