When a sodium atom transfers an electron to a chlorine atom, forming a sodium cation (Na+) and a chloride anion (Cl-), both ions have complete valence shells, and are energetically more stable. The reaction is extremely exothermic, producing a bright yellow light and a great deal of heat energy.
Answer:
151.94 u
Explanation:
The atomic mass of Eu is the <em>weighted average</em> of the atomic masses of its isotopes.
We multiply the atomic mass of each isotope by a number representing its relative importance (i.e., its <em>percent abundance</em>).
The atomic masses of Eu-151 and Eu-153 are 150.92 u and 152.92 u, respectively.
Set up a table for easy calculation.
0.4803 × 150.92 u = 72.472 u
0.5197 × 152.92 u = <u> 79.473 u
</u>
TOTAL = 151.94 u
Explanation:
1. Democritus proposes the existence of atoms
2. Dalton's atomic theory
3. J. J. Thomson discovers the electron
4. Rutherford's gold foil experiment
5. Bohr model
6. Schrödinger's Wave Mechanics model of the atom
The first idea about matter containing atoms dates back to Greek philosophers. One of them was Democritus .
In 1808 Dalton put forward his atomic theory
In 1897 J.J Thomson discovered cathode rays using his gas discharge tube experiment.
In 1911, Ernest Rutherford proposed the nuclear model of the atom using experiments on the gold foil.
Neils Bohr in 1913 suggested his own atomic model
Erwin Schrodinger formulated the wave equation of electrons
Learn more;
Dalton atomic theory brainly.com/question/1979129
Rutherford gold foil experiment brainly.com/question/1859083
#learnwithBrainly
Depends on the element it can by up to 3, 8, or maybe 16.
