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learning goals
- Understand the fundamental properties that separate metals, non-mentals, and metalloids.
An element is the simplest form of matter that cannot be broken down or built from simpler substances by any ordinary chemical or physical method. We are aware of 110 elements, 92 of which are naturally occurring while the rest are man-made. Elements are further classified into metals, nonmetals, and semimetals.
| metallic elements | non-metallic elements |
|---|---|
| Pronounced brightness (Glow) | No reflections, various colors. |
| Malleable and stretchable (flexible) like solids | brittle, hard or soft |
| It conducts heat and electricity. | bad drivers |
| Metal oxides are basic, ionic. | Non-metallic oxides are acids, compounds |
| cations in aqueous solution | Anions, oxyanions in aqueous solution |
Years
All elements except hydrogen, which form positive ions by donating electrons in chemical reactions, are called metals. Metals are therefore electropositive elements. They are characterized by their great brightness, hardness, sound resonance capacity and are excellent conductors of heat and electricity. Metals are solid under normal conditions, except mercury.
Physical properties of metals.
Metals are shiny, malleable, ductile, good conductors of heat and electricity. Other properties are:
- Condition: Metals are solid at room temperature, except mercury, which is liquid at room temperature (gallium is liquid on hot days).
- Seem: Metals have the property of reflecting light from their surface and can be polished, for example, gold, silver and copper.
- malleability:Metals can withstand hammering and can be formed into thin sheets known as sheets (a piece of golden sugar cubes can be pounded into a thin sheet that covers a football field).
- ductility:Metals can be processed into wires. A thin wire about 200 meters long can be made from 100 g of silver.
- Tenacity:All metals are hard except sodium and potassium, which are soft and can be cut with a knife.
- valor:Metals have 1 to 3 electrons in the outermost shell of their atoms.
- Drive: Metals are good conductors because they have free electrons. Silver and copper are the two best conductors of heat and electricity. Lead is the worst conductor of heat. Bismuth, mercury, and iron are also poor conductors.
- density: Metals are dense and very heavy. Iridium and osmium have the highest densities, while lithium has the lowest density.
- melting and boiling points: Metals have high melting and boiling points. Tungsten has the highest melting point, while silver has a low boiling point. Sodium and potassium have low melting points.
Chemical properties of metals.
Metals are electropositive elements that generally form basic or amphoteric oxides with oxygen. Other chemical properties are:
- electropositive character: Metals tend to have low ionization energies andthey normally lose electrons (meaning they arerusty) when subjected to chemical processesreactionsThey normally do not accept electrons. For example:
\[Na^0 \rightarrow Na^+ + e^-\]
\[Mg^0 \rightarrow Mg^{2+} + 2e^-\]
(Video) Physical Properties of Metals and Nonmetals - Part 1 | Don't Memorise\[Al^0 \rightarrow Al^{3+} + 3e^-\]
- The alkali metals are always 1+(lose the electron inSlower class)
- The alkaline earth metals are always 2+(loses both electrons inSlower class)
- The transition metal ions do not follow an obvious pattern, 2+is common and 1+mi 3+are also observed
- Compounds of metals with nonmetals are usuallyIonicIn nature
- Most metal oxides are basic oxides and dissolve in water to formmetal hydroxide:
metal oxide + water -> metal hydroxide
Of2Ö(S) +H2Ö(UE) -> 2NaOH(ac)
CaO(S) +H2Ö(UE) -> Ca(OH)2(ac)
- The metallic oxides show theirBasicchemical nature, reaction withacidsto formdiceand water:
metal oxide + acid -> salt + water
MgO(S) + HCl(ac) -> MgCl2(ac) +H2Ö(UE)
NiO(S) +H2SO4(ac) -> no4(ac) +H2Ö(UE)
Example
What is the chemical formula of aluminum oxide?
Solution
Al has a 3+ charge, the oxide ion is O2-, Assim Al2o3
Example
Would you expect it to be a solid, liquid, or gas at room temperature?
solutions
Metal oxides are characteristically solid at room temperature.
Example
Write the balanced reaction equation for the reaction of alumina with nitric acid:
Solution
metal oxide + acid -> salt + water
Alabama2o3(S) + 6HNO3(ac) -> 2Al(NOCHE3)3(ac) + 3H2Ö(UE)
no metals
Elements that tend to accept electrons in chemical reactions to form anions are called nonmetals. These are electronegative elements. They are opaque, brittle, and poor conductors of heat and electricity (except graphite). Nonmetals can be gaseous, liquid, or solid.
Physical properties of non-metals:
- physical state: Most nonmetals exist in two of the three states of matter at room temperature: gases (oxygen) and solids (carbon).
- Non-deformable and stretchable: Nonmetals are very brittle and cannot be wound into wires or sheets.
- Drive: They are poor conductors of heat and electricity.
- Seem:These have no metallic sheen and do not reflect light.
- conductivity: Poor conductors of heat and electricity
- melting and boiling points: The melting points of nonmetals aregenerallyinferior to metals
- Seven nonmetals exist under standard conditions such asdiatomic molecules:
- H2(GRAMS)
- norte2(GRAMS)
- o2(GRAMS)
- F2(GRAMS)
- Kl2(GRAMS)
- brother2(UE)
- UE2(UE) (volatile liquid - evaporates easily)
Chemical properties of non-metals.
- Nonmetals tend to gain or share electrons with other atoms. They have an electronegative character.
- Nonmetals tend to gain electrons when they react with metals (typicallyReaching the noble gas electron configuration)and the willanions:
no metal + metal -> sal
\[3Br_{2(l)} + 2Al_{(s)} \rightarrow 2AlBr_{3(s)}\]
- Entirely nonmetallic compounds are molecular (nonionic) substances.
- They usually form acidic or neutral oxides with oxygen, which react to form acids when dissolved in water:
non-metallic oxide + water -> acid
\[CO_{2(g)} + H_2O_{(l)} \rightarrow \underset{\text{carbonic acid}}{H_2CO_{3(aq)}}}\]
(carbonated water is slightly acidic)
- Non-metal oxides can combine with bases to form salts.
non-metallic oxide + base -> salt
\[CO_{2(g)} + 2NaOH_{(aq)} \rightarrow Na_2CO_{3(aq)} + H_2O_{(l)}\]
metaloide
Intermediate properties between metals and non-metals. Metalloids are useful in the semiconductor industry.
| Years | no metals | metaloide |
|---|---|---|
| Oro | oxygen | silicon |
| Talk | coal | boro |
| copper | hydrogen | Arsenic |
| Ferro | Nitrogen | antimony |
| mercurio | sulfur | Germany |
| zinc | Phosphor |
Physical properties of metalloids
- Condition: They are all solid at room temperature.
- Drive: Some metalloids such as silicon and germanium can function as electrical conductors under the right conditions, which is why they are called semiconductors.
-
Seem: siliconfor example it looks shiny but it isNOmalleable or stretchablefragile- a property of some nonmetals). It is a much worse conductor of heat and electricity than metals.
- solid solutions: can form alloys with other metals.
Chemical properties of metalloids.
- Its physical properties are more metallic, but its chemical properties are more non-metallic.
- The oxidation number of an element in this group can vary from +3 to -2 depending on the group.
Trends in metallic and non-metallic characters
metallic characterEsbut strongerfor the elements ofmore to the leftIt is part of the periodic table and tends todecrease as we move to the rightat any time (non-metallic character increases with increasing ionization values). Within any group of elements (columns)The metallic character increases from top to bottom.(Ionization values generally decrease as we go down the group).This general trend isNOnecessarily with what is observedtransition metals.
employees and tasks
mike blaber(Florida State University)
(Video) You Can MELT METAL In Your HAND! - Liquid Metal Science ExperimentsBinod Shrestha(University of Lorraine)