4 get of helium is 1 mole
Answer:
C. They don't react with other elements to form compounds
Explanation:
The elements in Group 18 of the periodic table are called "inert", or noble gases.
These elements have their valence shell (the outermost shell of the atom) full of electrons, so they do not gain/give off electrons, and therefore, they do not react with other elements, so they do not form compounds.
In fact, normally the elements try to gain/give off electrons in order to fullfill their outermost shell (the valence shell). For instance, an atom that has 1 electron only in its valence shell, try to "give away" this electron in order to have its outermost shell completed. On the other hand, an atom which has 7 electrons in its valence shell tries to "gain" one electron in order to fullfill the valence shell.
Noble gases, instead, have already 8 electrons in their valence shell, so their valence shell is already completed, therefore they do not react with other elements, and therefore they are called "inert".
The correct answer should be D :)
De Broglie's wave equation describes that particles have wave properties. The equation is
λ = h/mv
Where λ is the wave length of the particle (m), h is the Planck's constant (6.62607 x 10⁻³⁴J s), m is the mass of a particle (kg) and v is the velocity (m/s).
λ = ?
h = 6.62607 x 10⁻³⁴<span> J s
m =200 g = 0.2 kg
v = 20 m/s
</span>By substitution,
λ = 6.62607 x 10⁻³⁴ J s / (0.2 kg x 20 m/s)
λ = 1.66 x 10⁻³⁴ m
Hence, the wavelength of the 200 g ball 1.66 x 10⁻³⁴ m.
There are three subatomic particle that are present in an atom. These are electrons, protons, and neutrons. Among these three, I believe the <span>subatomic particle that plays the greatest part in determining the properties of and element would be the electron. It is what determines how the element would react in different conditions.</span>
