List all possible routes of entry into a building by radon

Soil, Building materials, Outdoor air, Drinking water, Domestic gas

Explanation:

Radon is a radioactive gas of natural origin, coming from the decay of radio-226 found in a small  proportion in the air that is breathed and is responsible for a fraction of the natural radiation that human beings receive.

Natural radiation is part of the environment and its main components are cosmic radiation, those coming from  the radionuclides, present in soils and rocks, and those of radioactive substances, found in food, water and  air

Ground

In isolated constructions or on the ground floors of buildings without basement, the most important source of radon is the radius present in the  ground. The concentration of radius in the soil is generally between 10 and 50 Bq / kg, although it can reach very high values superior. The average value is around 40 Bq / kg. Radon concentrations in soils vary between 10,000 and 50,000 Bq / m3

Construction materials

Construction materials are, in general, the second most important source of radon indoors. Radon emission from  the construction materials depends not only on the concentration of radius in them but also on factors such as the  fraction of radon produced that is released from the material, the porosity of the material and the surface preparation and finish of the  walls. It is common to find among the building materials products with a radium and thorium content of up to 50 Bq / kg.

Outside air

Because of its low radon content, outside air normally acts as a dilution factor. However, in some cases, in  buildings constructed with materials with a very low radio content outside air can act as a source of radon.

Water for consumption

The use for domestic use of groundwater with a high concentration of radon can mean, when released, a  increase of its concentration in air, especially in bathrooms where the hot water is in motion and the process of  release is favored.

Household gas

In some areas the natural gas used for cooking and heating contains high concentrations of radon that are released into the  burn it down. Generally this is not a significant source and is also very variable depending on the changes in the supply of  fuel.

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance