Marina, Mario and João Chemistry 10A

The second group in the periodic table

is the group of the alkaline earth

metals. It consists of the elements

beryllium, magnesium, calcium,

strontium, barium and radium. They

have plenty of different applications,

ranging from the manufacture of

fireworks to ingredients in dental and

health products.

Generally, they have a set of

common characteristics, like color,

format and reactivity. This is due to

their similar electrical configuration:

all elements in this group have two

electrons in their outermost energy

level and end in the "s" orbital. They

are very reactive, so much that they

can't be found alone in nature, and

quickly lose electrons to other

elements, especially to halogens and

other non-metals. They have a silvery

color and are relatively soft and shiny.

Applications Each alkaline earth metal has a

different use. Beryllium, the one with

the smallest number of protons, is

found primarily in gems such as

emeralds and aquamarines, in the

compound beryl, made of beryllium,

aluminum and silicon. It is also used

in the place of glass in x-ray tubes,

since it allows more of the radiation to

go through; and is used in metal alloys

in a very low concentration (up to 2%

only) to make them stronger, more

resistant and more stable at high

temperature.

Magnesium, the next metal in line,

is essential to life. It is in the core of

chlorophyll, the pigment present in

plants that plays a critical role in

photosynthesis, the transformation of

carbon dioxide into oxygen, making

life possible in our planet. However, it

also has a darker use. Magnesium was

widely used during war time in

bombs, flares, and bullets due to its

incendiary quality. Besides that, it

used to be a primary component in

aircrafts and other military equipment.

Calcium, perhaps, is the most well-

known alkaline earth metal. Due to its

vital role in our body, we all need a

certain amount of calcium ingestion. It

Beryllium is a main element in gems such as emeralds and aquamarines.

is necessary for the proper growth of

our teeth and bones, and regulates

heartbeat and blood pressure. Outside

of our body, calcium also has its uses.

Limestone, a material made of

calcium, has since long been used in

building materials; chalk, a compound

of calcium and carbon, is well-used in

classrooms all around the world; and

calcium is also used for the paper,

dairy and metallurgical industries.

Strontium is a lesser-known alkaline

earth metal. In the past, it was a quite

polemic element, since one of its

isotopes was the byproduct of nuclear

explosions. However, nowadays, its

only use is in firework making, where

its bright red flame is very useful.

Barium has two main uses. It is used

as lubricant in well-drilling operations

and for engine cleaning in general. In

the area of health-care, it has a peculiar

utilization: doctors give barium sulfate

for the patients about to take x-rays,

since this element can easily absorb

radiation, making it safer for the

patient and increasing the accuracy of

the exams.

Radium is the only radioactive

metal from this group. Formerly, it

was used as treatment for cancer and

in signs and clocks, due to its glowing

property. However, its use has since

declined, because it was discovered

that radium was very hazardous to

life, and there were many workers in

the clock making industry that died

because of prolonged exposure to this

element. Besides that, scientists soon

found out that, in cancer treatment,

radium provided more problems than

benefits, sealing once and for all the

use of this radioactive element.