Answer:
number of valence electrons
Explanation:
All of the elements in group 17, also known as group 7A, have 7 valence electrons.
No two elements have the same atomic number nor atomic mass in elemental form.
Halogens may have any number of isotopes.
Answer:
1. Atom absorbs energy from a source
2. Electron becomes unstable because it is quantized
3. Electron jumps to a higher energy level
4. Energy is released in the form of light
5. Electron falls to a lower energy level
Crystalline silica is hazardous when small particles are
inhaled. They can penetrate deep into the lungs and cause disabling and
sometimes fatal lung diseases including silicosis, lung cancer and kidney
disease. The particles of crystalline silica enters the lungs and causes the
formation of scar tissue known as silicosis, thus reducing the lungs’ ability
to take in oxygen.
Answer:
It refers to the number of protons in the nucleus of an atom
Thompson suggested that the atom is a positively charged sphere where electrons are embedded inside it.
