What is the electronegativity difference
between sodium and chlorine?

2.23 is the difference.

Explanation: Sodium has an electronegativity of 0.93 and Chlorine has an electronegativity of 3.16, so when Sodium and Chlorine form an ionic bond, in which the chlorine takes an electron away from sodium, forming the sodium cation, Na+, and the chloride anion, Cl-.

the leaf is an organ of a typical plant, and the main functions are to complete photosynthesis and allow the plant to exchange gas, just like how we have the respiratory system. leaves have the stomata, which collects maintains co2 and o2 levels. this is necessary for cell metabolism. the leaf also collects sunlight using chloroplasts. succinctly, leaves own a pivotal role in sustaining plant life.

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.