Beryllium is a chemical element with
the symbol Be and atomic number 4. A bivalent element,
beryllium is a steel grey, strong, light-weight yet
brittle, alkaline earth metal. It is primarily used as a
hardening agent in alloys, most notably beryllium
copper.
It has one of the highest melting points of the light
metals. The modulus of elasticity of beryllium is
approximately a third greater than that of steel. It has
excellent thermal conductivity and is nonmagnetic.
from- Wikipedia
Magnesium
Magnesium metal and alloys are highly
flammable in their pure form when molten, as a powder,
or in ribbon form. Burning or molten magnesium metal
reacts violently with water. Magnesium powder is an
explosive hazard. One should wear safety glasses while
working with magnesium, and if burning it, these should
include a heavy U.V. filter, similar to welding eye
protection. The bright white light (including
ultraviolet) produced by burning magnesium can
permanently damage the retinas of the eyes, similar to
welding arc burns.[4]
Water should not be used to extinguish magnesium
fires, because it can produce hydrogen which will feed
the fire.
Carbon dioxide fire extinguishers should not be used
either, because magnesium can burn in carbon dioxide
(forming magnesium oxide, MgO, and carbon). A Class D
dry chemical fire extinguisher should be used if
available, or else the fire should be covered with sand
or magnesium foundry flux. An easy way to put out small
metal fires is to place a polyethylene bag filled with
dry sand on top of the fire. The heat of the fire will
melt the bag and the sand will flow out onto the fire.
from-wikipedia
Dry Ice
and Magnesium Reaction
Calcium
Calcium is a soft grey alkaline earth
metal, and is the fifth most abundant element in the
Earth's crust. It is essential for living organisms,
particularly in cell physiology, and is the most common
metal in many animals.
Chemically calcium is reactive and moderately soft
for a metal (though harder than lead, it can be cut with
a knife with difficulty). It is a silvery metallic
element that must be extracted by electrolysis from a
fused salt like calcium chloride.[1] Once produced, it
rapidly forms a grey-white oxide and nitride coating
when exposed to air. It is somewhat difficult to ignite,
in character rather like magnesium, but when lit, the
metal burns in air with a brilliant high-intensity red
light. Calcium metal reacts with water, evolving
hydrogen gas at a rate rapid enough to be noticeable
(unlike its sister magnesium) but not fast enough at
room temperature to generate much heat. Part of the
slowness of the calcium-water reaction results from the
metal being partly protected by insoluble white calcium
hydroxide. In water solutions of acids where the salt is
water soluble, calcium reacts vigorously.
from-wikipedia
Strontium
An alkaline earth metal, strontium is a
soft silver-white or yellowish metallic element that is
highly reactive chemically. The metal turns yellow when
exposed to air.
Due to its extreme reactivity to air, this element
occurs naturally only in compounds with other elements,
as in the minerals strontianite and celestite.
In its pure form strontium is extremely reactive with
air and spontaneously combusts. It is therefore
considered to be a fire hazard.
The human body absorbs strontium as if it were
calcium. Due to the elements being sufficiently similar
chemically, the stable forms of strontium do not pose a
significant health threat, but the radioactive 90Sr
can lead to various bone disorders and diseases,
including bone cancer.
from-wikipedia
Barium
Barium is a soft silvery
metallic alkaline earth metal. It is never found in
nature in its pure form due to its reactivity with air.
Its oxide is historically known as baryta but it reacts
with water and carbon dioxide and is not found as a
mineral.
Barium is a metallic element that is chemically
similar to calcium but more reactive. This metal
oxidizes very easily when exposed to air and is highly
reactive with water or alcohol, producing hydrogen gas.
Burning in air or oxygen produces not just barium oxide
(BaO) but also the peroxide. Simple compounds of this
heavy element are notable for their high specific
gravity. This is true of the most common barium-bearing
mineral, its sulfate barite BaSO4, also called 'heavy
spar' due to the high density (4.5 g/cm³).
All water or acid soluble barium compounds are
extremely poisonous. At low doses, barium acts as a
muscle stimulant, while higher doses affect the nervous
system, causing cardiac irregularities, tremors,
weakness, anxiety, dyspnea and paralysis. This may be
due to its ability to block potassium ion channels which
are critical to the proper function of the nervous
system.
Radium
Radium was discovered by Marie Sklodowska
Curie, a Polish chemist, and Pierre Curie, a French
chemist, in 1898. Marie Curie obtained radium from
pitchblende, a material that contains uranium, after
noticing that unrefined pitchblende was more radioactive
than the uranium that was separated from it. She
reasoned that pitchblende must contain at least one
other radioactive element. Curie needed to refine
several tons of pitchblende in order to obtain tiny
amounts of radium and polonium, another radioactive
element discovered by Curie. One ton of uranium ore
contains only about 0.14 grams of radium. Today, radium
can be obtained as a byproduct of refining uranium and
is usually sold as radium chloride (RaCl2) or
radium bromide (RaBr2) and not as a pure
material.
Radium had been used to make self-luminous paints for
watches, aircraft instrument dials and other
instrumentation, but has largely been replaced by
cobalt-60, a less dangerous radioactive source. A
mixture of radium and beryllium will emit neutrons and
is used as a neutron source. Radium is used to produce
radon, a radioactive gas used to treat some types of
cancer. A single gram of radium-226 will produce 0.000l
milliliters of radon a day.
Radium is about one million times more active than
uranium. The lab notebooks used by the Curies are too
highly contaminated to be safely handled today.
Radium was discovered by Marie Sklodowska
Curie, a Polish chemist, and Pierre Curie, a French
chemist, in 1898. Marie Curie obtained radium from
pitchblende, a material that contains uranium, after
noticing that unrefined pitchblende was more radioactive
than the uranium that was separated from it. She
reasoned that pitchblende must contain at least one
other radioactive element. Curie needed to refine
several tons of pitchblende in order to obtain tiny
amounts of radium and polonium, another radioactive
element discovered by Curie. One ton of uranium ore
contains only about 0.14 grams of radium. Today, radium
can be obtained as a byproduct of refining uranium and
is usually sold as radium chloride (RaCl2) or
radium bromide (RaBr2) and not as a pure
material.
