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.
Stability of atoms is determined by neutron:proton ratio. This n/p ratio is 1:1 for elements below atomic number 20. Hope this helps.
Ba2+ and Cu2+, and Sr2+ and Li+
The pressure of a gas is the force that the gas exerts on the walls of its container. When you blow air into a balloon, the balloon expands because the pressure of air molecules is greater on the inside of the balloon than the outside. Pressure is a property which determines the direction in which mass flows.
