Rank these elements according to first ionization energy. na, li, rb, k

Explanation:

Ionization energy is defined as the energy required to remove most loosely bound electron from a gaseous atom or ion.

When we move down a group then there occurs a decrease in ionization energy. This is because size of atom increases down the group and valence shell is away from the nucleus of the atom.

Due to this there will be less force of attraction between the nucleus and valence electrons. As a result, it becomes easier to remove the valence electron.

For example, Na, Li, Rb and K are all group 1 elements.

Rb being the largest in size will have low ionization energy whereas Li being the smallest will have highest ionization energy.

Therefore, given elements are arranged from highest to least ionization energy as follows.

                                 Li > Na > K > Rb

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.

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.