Tag Archives: metals

What Is Tin Cry? – Explanation of the Term and How To Hear It

Question: What Is Tin Cry?

To hear tin cry, simply bend a piece of tin metal. The sound is faint, so listen closely! (Jurii))

To hear tin cry, simply bend a piece of tin metal. The sound is faint, so listen closely! (Jurii)

Answer: Tin is the metal that is atomic number 50 on the periodic table. Tin cry is the sound that is made when a bar of tin metal is bent. The sound is caused by the shearing of the crystals in the metal. When tin solidifies, crystal twinning occurs, where separate crystals share lattice points and overgrow each other. The tin cry actually is a relatively soft sound, sort of a crackling whine.

How To Make Tin Cry

You can make a bar of tin cry simply by bending it. The sound will be emitted up to the point at which the metal breaks. Tin has a relatively low melting point, 232 °C, so you can melt the tin and allow it to recrystallize to repeat the process again and again.

Other Metals That Cry

The cry is a characteristic of solid tin, but the phenomenon is not exclusive to this element. Niobium, indium and gallium will cry when bent as the crystals shear against each other.

Alkaline Earth Metals

The alkaline earth metals are 6 elements found in the second column of the periodic table. (Todd Helmenstine)

The alkaline earth metals are 6 elements found in the second column of the periodic table. (Todd Helmenstine)

The alkaline earth metals or alkaline earths are a set of six elements found in the second group (column) of the periodic table.  Atoms of each of these elements have two electrons in the outer electron shell. Take a look at the elements in this group and their common properties:

List of the Alkaline Earth Metals

There are six alkaline earths. In order of increasing atomic number, they are:

Alkaline Earth Metal Properties

These are crystals of magnesium. The other alkaline earth metals have a similar appearance and properties. (Mark Fergus, CSIRO)

These are crystals of magnesium. The other alkaline earth metals have a similar appearance and properties. (Mark Fergus, CSIRO)

Because each atom has two valence electrons, elements of this group share several common characteristics:

  • Atoms have a full outer s electron shell (2 electrons), which means these elements form cations with a 2+ charge and have a 2+ oxidation state.
  • Atoms have a low electron affinity and low electronegativity.
  • All of the alkaline earths are shiny, silver-colored metals at ordinary temperatures and pressure.
  • These metals are malleable and ductile.
  • The alkaline earth metals tend to be soft, with relatively low densities, melting points, and boiling points for metals. The melting points and boiling points are still much higher than for nonmetals. While soft, these elements are harder than those of the alkali metal group.
  • Elements of this group are moderately reactive, with reactivity increasing as you move down the periodic table (i.e., strontium is more reactive than calcium).
  • The alkaline earth metals are found in compounds, not free in nature.
  • The alkaline earths readily react with halogens (Cl, Br, etc.) to form halides. They also react with oxygen to form oxides.
  • While not a property per se, it’s worth noting all of the alkaline earth elements are named for their oxides (the alkaline earths), which had the names beryllia, magnesia, lime, strontia, and baryta.

Alkali Metal Properties

Alkali Metals Group (Todd Helmenstine)

This periodic table is highlighted to identify the alkali metals group of elements. (Todd Helmenstine)

The alkali metals are the elements located in group IA of the periodic table (the first column). The key characteristic these elements share in common is that they all have one electron in the outer electron shell. This lone electron is loosely bound, making this a set of reactive metallic elements.

List of the Alkali Metals

Note the element missing from most lists of alkali metals is hydrogen. Hydrogen is an alkali metal when it’s found in its metallic state. Under ordinary temperatures and pressures, hydrogen occurs as a gas and has the properties of a nonmetal.

Alkali Metal Properties

Rubidium Metal Sample ( Dnn87)

Like other alkali metals, rubidium is a shiny, silver-colored metal. The pure element reacts in air or water, so it’s kept in a sealed container.

The lone outer shell electrons leads the alkali metal elements to share several common properties:

  • The one outer electron is easily lost, forming the univalent (1+) cation (e.g., Na+).
  • Alkali metals are typically less dense than other metals.
  • Atoms of alkali metals have the largest atomic radii of elements in their periods.
  • Alkali metals are highly reactive elements. In particular, they readily react with halogens and other nonmetals. The pure metals react with oxygen in air and with water. As you move down the group, reactivity increases. A piece of sodium metal in water will burn; a piece of cesium metal in water will explode.
  • Atoms have low ionization energies.
  • Alkali metal atoms have low electronegativity values.
  • Unlike most metals, alkali metals tend to be soft and have low melting points. You can cut sodium metal with a butter knife. The melting point of cesium is low enough it will melt from the heat of your hand or in a warm room.
  • Like other metals, alkali metals tend to be shiny and metallic in appearance, as well as good conductors of electricity and heat.

 

 

What Is a Heavy Metal?

A heavy metal, in the general sense, is a metal which is toxic and has a high density, specific gravity or atomic weight. Examples of heavy metals include lead, mercury and cadmium.

Is “Heavy Metal” a Misleading Term?

Coin Floating on Liquid Mercury, a Heavy Metal (Alby)

Coin Floating on Liquid Mercury, a Heavy Metal (Alby)

However, according to the International Union of Pure and Applied Chemistry or IUPAC, the term “heavy metal” may be a “meaningless term” because there is no standardized definition for a heavy metal. Some light metals or metalloids are toxic, while some high-density metals are not. For example, cadmium generally is considered a heavy metal, with an atomic number of 48 and specific gravity of 8.65, while gold typically is not toxic, even though it has an atomic number of 79 and specific gravity of 18.88. For a given metal, the toxicity varies widely depending on the allotrope or oxidation state of the metal. Hexavalent chromium is deadly; trivalent chromium is nutritionally significant in many organisms, including humans.

See a List of all Elements That Are Metals

Periodic Table Trends

The Periodic Table is called this not just because it is a table of the elements, but because it is arranged to reflect the periodic trends of the elements.

Periodic Table Trends

 

This table shows the periodic table trends of six different physical properties of the elements: atomic radius, electron affinity, electronegativity, ionization energy, and metallic/nonmetallic character.

Atomic radius is half the distance between two identical atoms touching each other.

  • atomic radius increases as you move right to left
  • atomic radius increases as you move down

As you move across the periodic table from right to left, each element contains one more electron and one more proton. The electrons form shells and are attracted strongly to the positive charge in the nucleus, pulling the shells closer to the center and effectively making the atom smaller with the addition of each proton. As you move down the periodic table, the valence of the the atom remains the same, but there are more filled electron shells between the outer electrons and the positive nucleus. These outer shells are shielded from the positive charge of the nucleus by layers of electrons and the effective charge they experience is less than the element above them. The outer electrons are not held as tightly as the outer electrons of the elements above them on the table.

Electron Affinity is the ability of an atom to accept an electron. It is measured by the energy change in the atom as an electron is added to the gaseous form of the atom.

  • electron affinity increases as you move left to right
  • electron affinity decreases as you move down

Atoms with stronger nuclear charge tend to have higher electron affinities as you move across the table. As you move down, the outer electron is both shielded from the nucleus by filled shells and physically further away. Both of these reduce the force of attraction between the nucleus and the added electron.

Electronegativity is the measure of attraction between the atom’s nucleus and electrons in a chemical bond. In general, the higher the electronegativity, the stronger the force of attraction between bonded electron and the atom nucleus.

  • electronegativity increases as you move left to right across the table
  • electronegativity decreases as you move down the table

A related term is electropositive. Think of it as the opposite of electronegativity. Atoms with low electronegativity are highly electropositive.

Ionization Energy is the energy needed to remove an electron from a gaseous atom. The tighter the nucleus holds an electron, the more energy needed to remove it.

  • ionization energy increases as you move left to right across the table
  • ionization energy decreases as you move down the table

Metallic and Nonmetallic Characteristics are a group of physical properties. As you move up and across from the bottom left of the table, the elements begin to take on the characteristics of nonmetals. Moving the opposite way, the elements take on properties of metals. For a more detailed examination of the difference, check out metals, metalloids and nonmetals.

List of Metals

Metal Elements

The highlighted elements are considered the metal elements.

Most elements can be considered metals. They are grouped together in the middle to the left hand side of the periodic table. The metals consist of the alkali metals, alkaline earths, transition metals, lanthanides and actinides.

Properties of Metals

The metals share several common properties, including:

  • solid at room temperature (with the exception of mercury)
  • usually shiny
  • high melting point
  • good conductor of heat
  • good conductor of electricity
  • low ionization energies
  • low electronegativities
  • malleable – able to be pounded into sheets
  • ductile – can be pulled into wire
  • high density (exceptions: lithium, potassium and sodium)
  • corrodes in air or seawater
  • loses electrons in reactions

List of Metals

This is a list of metals in order of increasing atomic number.

 NUMBER SYMBOLELEMENT
3LiLithium
4BeBeryllium
11NaSodium
12MgMagnesium
13AlAluminum
19KPotassium
20CaCalcium
21ScScandium
22TiTitanium
23VVanadium
24CrChromium
25MnManganese
26FeIron
27CoCobalt
28NiNickel
29CuCopper
30ZnZinc
31GaGallium
37RbRubidium
38SrStrontium
39YYttrium
40ZrZirconium
41NbNiobium
42MoMolybdenum
43TcTechnetium
44RuRuthenium
45RhRhodium
46PdPalladium
47AgSilver
48CdCadmium
49InIndium
50SnTin
55CsCesium
56BaBarium
57LaLanthanum
58CeCerium
59PrPraseodymium
60NdNeodymium
61PmPromethium
62SmSamarium
63EuEuropium
64GdGadolinium
65TbTerbium
66DyDysprosium
67HoHolmium
68ErErbium
69TmThulium
70YbYtterbium
71LuLutetium
72HfHafnium
73TaTantalum
74WTungsten
75ReRhenium
76OsOsmium
77IrIridium
78PtPlatinum
79AuGold
80HgMercury
81TlThallium
82PbLead
83BiBismuth
84PoPolonium
87FrFrancium
88RaRadium
89AcActinium
90ThThorium
91PaProtactinium
92UUranium
93NpNeptunium
94PuPlutonium
95AmAmericium
96CmCurium
97BkBerkelium
98CfCalifornium
99EsEinsteinium
100FmFermium
101MdMendelevium
102NoNobelium
103LrLawrencium
104RfRutherfordium
105DbDubnium
106SgSeaborgium
107BhBohrium
108HsHassium
109MtMeitnerium
110DsDarmstadtium
111RgRoentgenium
112CnCopernicium
113UutUnuntrium
114FlFlerovium
115UupUnunpentium
116LvLivermorium



List of Nonmetals

Nonmetal Elements

The highlighted elements are the nonmetal elements.

The nonmetal elements occupy the upper righthand corner of the periodic table. These elements have similar chemical properties that differ from the elements considered metals.

The nonmetal element group is a subset of these elements. The nonmetal element group consists of hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur and selenium.

Hydrogen acts as a nonmetal at normal temperatures and pressure and is generally accepted to be part of the nonmetal group.

Properties of nonmetals include:

  • dull, not shiny
  • poor conductor of heat
  • poor conductor of electricity
  • high ionization energies
  • high electronegativity
  • not malleable or ductile, usually brittle
  • lower density (when compared to metals)
  • lower melting point and boiling points (when compared to metals)
  • gains electrons in reactions

This is a list of the nonmetal elements in order of increasing atomic number.

 NUMBER SYMBOLELEMENT
1HHydrogen
2HeHelium
6CCarbon
7NNitrogen
8OOxygen
9FFluorine
10NeNeon
15PPhosphorus
16SSulfur
17ClChlorine
18ArArgon
34SeSelenium
35BrBromine
36KrKrypton
53IIodine
54XeXenon
85AtAstatine
86RnRadon
117UusUnunseptium
118UuoUnunoctium