German scientist Döbereiner was one responsible for grouping elements into triads based on most notably atomic mass, many of which can be found in the periodic table to be in a pattern (for example <span><span>Iron </span><span>Cobalt </span><span>Nickel, elements 26, 27, 28)</span></span>
Answer: Multiple covalent bonds may occur in atoms that contain carbon,nitrogen, or <u><em>oxygen</em></u>.
Answer:
chemical symbol= Cl ( chlorine)
electrons= 17
2p electrons = 6
The elements in which electrons are progressively filled in 4f-orbital are called lanthanoids.
There are 15 metallic chemical elements called lanthanoids.
Those elements are with atomic numbers from 57 to 71.
Lanthanoids belong to f-block elements because of the filling of the 4f-orbitals.
One of the lanthanoids, lutetium (chemical symbol Lu) has 14 electrons if 4f orbitals.
Electron configuration of lutetium: [Xe] 4f14 5d1 6s2
f-orbitals are similar to the d orbital, but cut in half (eight lobes instead of four).
Lanthanoids are used not as materials in catalysts, alloys, lasers and cathode-ray tubes.
More info about lanthanoids: brainly.com/question/24413965
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Answer:
all of these are properties of metalloids
