(2) hydrogen carbonate (4) oxalate
Answer is (2) - hydrogen carbonate
Explanation:
NaHCO₃ is an ionic compound which is made from Na⁺ and HCO₃⁻ ions. The decomposition is
NaHCO₃ → Na⁺ + HCO₃⁻
Among the resulted ions, Na⁺ is a monatomic ion while HCO₃⁻ is a polyatomic ion.
Polyatomic ions mean ions which are made of two or more different atoms.
HCO₃⁻ is made from 3 atoms as H, C and O. The name of HCO₃⁻ ion is bicarbonate or hydrogen carbonate.
B electrons move to higher energy levels
** C electrons are gained by an atom in
D. člectrons fall bàok to lower energy levels
Answer:
option d= electrons fall back to the lower energy levels
Explanation:
Excitation:
When the energy is provided to the atom the electrons by absorbing the energy jump to the higher energy levels. This process is called excitation. The amount of energy absorbed by the electron is exactly equal to the energy difference of orbits.
De-excitation:
When the excited electron fall back to the lower energy levels the energy is released in the form of radiations. this energy is exactly equal to the energy difference between the orbits. The characteristics bright colors are due to the these emitted radiations. These emitted radiations can be seen if they are fall in the visible region of spectrum.
Fluorescence:
In fluorescence the energy is absorbed by the electron having shorter wavelength and high energy usually of U.V region. The process of absorbing the light occur in a very short period of time i.e. 10 ∧-15 sec. During the fluorescence the spin of electron not changed.
The electron is then de-excited by emitting the light in visible and IR region. This process of de-excitation occur in a time period of 10∧-9 sec.
Phosphorescence:
In phosphorescence the electron also goes to the excitation to the higher level by absorbing the U.V radiations. In case of Phosphorescence the transition back to the lower energy level occur very slowly and the spin pf electron also change.
The characteristic color (spectrum) of an element is produced when its electrons fall back to lower energy levels. They absorb energy to jump to a higher level, then emit it in the form of light of a specific wavelength when returning to their original or lower level.
The characteristic bright-line spectrum (color) of an element is produced when electrons fall back to lower energy levels (Option D). This process is part of the quantum mechanical model of the atom, particularly in the field of spectroscopy. Each element possesses unique energy levels. When an electron in an atom absorbs energy, it jumps to a higher energy level. When the electron returns to its original or lower energy level, it emits energy in the form of light of a specific wavelength. This is viewed as a unique color in the spectrum.
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Answer: 3.64 hours
Explanation:
Formula of Average speed :
Given : Distance = 200km ; Average speed = 55 km/ hr
To find : Time
Substitute values for distance and average speed in the above formula , we get
Hence, it would take 3.64 hours for a car to travel 200km .