Answer:
it is less dense than oxygen gas.
Explanation:
Hydrogen is the simplest chemical element that exists. The symbol for the chemical element Hydrogen is "H" and it is a colourless, tasteless, odorless, and highly flammable gas.
Hydrogen is a chemical element found in group (1) of the periodic table and as such it has one (1) electrons in its outermost shell. Therefore, Hydrogen has an atomic number of one (1) and a single valence electrons because it has only one proton and one electron in its nucleus.
In Chemistry, the properties of a chemical element that can be observed and measured without changing its chemical nature is known as a physical property. It includes density, color, freezing point, opacity, smell, melting point, viscosity, etc.
Hence, the statement which describes a physical property of hydrogen is that it is less dense (density) than oxygen gas.
Answer: Thats false the Russians were the first
Explanation:
Answer: half life
Explanation: Radioactive decay follows first order kinetics and the time required for the decay of a radioactive material is calculated as follows:
t= time required
k= disintegration constant
x= amount of substance left after time t
a= initial amount of substance
when one half of the sample is decayed, one half of the sample remains and t can be represented as 
at 
, 
Answer:
it gets rust and could not run properly
