### gas:

Nitrogen dioxide
* Some nitrogen dioxide comes from burn coal
* Some nitrogen dioxide has brown color
  - characteristic brown color
* can also react in the atmosphere to form ozone, acid rain, and particles.
* can cause eye, nose, and throat and respiratory tract irritation
  - respiratory illness and increase breathing difficulty
  - damage the respiratory tract
  - harm humans at elevated levels above the national standard
  - irritate the lungs and lower the resistance to respiratory infections
  - result in instant death o permanent lung damage
* is chemical compounds
  - developed in both electric arc and torch welding
  - very toxic
+ Nitrogen dioxide, Safety: Nitrogen compounds :: Oxides
  * Nitrogen dioxide is very toxic. It is also released by some cars, polluting the atmosphere. It has a bad odor. It can stop the nose from smelling, making the person unaware that they are breathing toxic fumes.

### gas:

Noble gas
* All Noble Gases have a full outer energy level.
* Most noble gases have energy
  - high energy
* Most noble gases possess energy
* Noble Gasses are colorless gasses that are extremely unreactive.
* Some noble gases have applications
  - direct application in medicine
  - elements
  - forces
  - isotopes
* Some noble gases have many applications
  - important applications
  - stable isotopes
  - weak forces
* are chemical elements
  - special because they have a full valence shell
  - the natural places to study nuclear effects in nature
  - typically highly unreactive except when under particular extreme conditions
* are very stable - meaning that they do very little chemistry
  - volatile
* have completely filled outer shells, so they are stable
  - full outer levels
  - great stability, as evidence by reluctance to form compounds
  - the outer orbits filled
* is an element
+ Xenon
  * Xenon is a belongs to the group of the noble gases. Noble gases are very unreactive. However, in 1962, chemists have found that xenon can react with fluorine under special conditions. Those special conditions are high pressure and high temperature. It is not known why xenon behaves differently under these circumstances. There are also some compounds with oxygen. The gas is not very reactive, because if fulfills the octet rule.

Noxious gas
* can seep from volatile materials.
* es are harmful humours that cause an imbalance in the body.
* pop into the atmosphere with each lethargic wave.

Oxygen gas
* Most oxygen gases have atoms
  - oxygen atoms
  - weight
  - sustain life
* Some oxygen gases are produced by photosynthesis.

Phosphine
* is pesticide
* occurs as a colorless, flammable gas that is slightly soluble in water.

Propane gas
* can ignite easily.
* gas derived from oil.
* has an odorant added to help identify any gas leak.
* is available in bulk quantities at competitive prices
  - converted into carbon dioxide at just the right temperature and humidity
  - heavier than air
  - produced in America
  - today's best value in water heating
* is used as fuel, with an agent to produce artificial smoke
  - to create the flame effects
* liquefied by cooling much, much better cryo-agent than is isopentane.

### gas:

Radon gas
* All radon gas has a parent nucleus of lead.
* Most radon gases enter homes.
* can also accumulate in private wells and be released into the home when water is used
  - enter the home through well water
  - escape through the newly formed cracks, and electrical resitivity decreases
  - exist in homes without basements
  - move through small spaces in the soil and rock on which a house is built
  - seep in from the soil
* enters the home naturally through the soil foundation.
* is radioactive, and radon itself comes from the decay of radioactive uranium.
* occurs naturally in most places on the planet.