Question in incomplete, complete question is:
Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle (electron) with a kinetic energy (Ek) of 
. What is the de Broglie wavelength of this electron (Ek = ½mv²)?
Answer:
is the de Broglie wavelength of this electron.
Explanation:
To calculate the wavelength of a particle, we use the equation given by De-Broglie's wavelength, which is:
where,
= De-Broglie's wavelength = ?
h = Planck's constant = 
m = mass of beta particle = 
= kinetic energy of the particle =
Putting values in above equation, we get:
is the de Broglie wavelength of this electron.
Answer:
Electronegativity generally increases from left to right across a period,
Explanation:
The true statement from the given choices is that electronegativity generally increases from left to right across a period.
Electronegativity is the measure of the relative tendency with which an atom of the element attract valence electrons in a chemical bond.
Across a period electronegativity increases from left to right and decreases down the group.
This is due to reduction in metallic properties as we move across the period from left to right.
1 meter = .001 kilometers so 4.5 x 10^3 = 4500 so .001 x 4500 = 4.5 kilo
Condensation is when vapor liquidizes and gathers on top of a surface, while boiling is turning a liquid into a gas or vapor. They are opposites. In the first, the molecules of the substance split and separate and increase the volume, while in the second they come together and reduce the volume.
Answer:
Diameter He = 0,1 nm.
Explanation:
Km to nm:
⇒ Diameter He = 1.0 E-13 Km * ( 1000 m / Km ) * ( 1 E9 nm / m )
⇒ Diameter He = 0.1 nm
