Magnesium is a group 2 metal which exists as a number of isotopes and forms many compounds. Magnesium ions produce no emission of absorption lines in the visible region of the electromagnetic spectrum. Suggest why most magnesium compounds tested in a school laboratory show traces of yellow in the flame

Traces of sodium impurity

Explanation:

Metal ions are identified by a characteristic colour imparted to flame by the metal ion solution. Various metals have various colours which they impart to a flame.

The energy of a flame is not sufficient for the excitation of electrons of Mg to a higher energy level. As a result of this, Mg do not give any color in Bunsen flame.

However, a few tinges of yellow-orange colour which is characteristic of sodium metal do appear when magnesium ions are exposed to a flame as a consequence of traces of sodium impurity in the magnesium ion solution.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.