Answer:
Hydrogen spectrum
Explanation:
Balmer series - Observed in the visible region
Brackett series - Observed in the infrared region
Paschen series - Observed in the infrared region
Lyman series - Observe in the Ultraviolet region.
Answer:
1. 
2. 
Explanation:
An ion is formed when an atom that is said to be neutral gains or losses electrons.
It is thought that a negative ion (anion) is produced as it gains electrons and a positive ion (cation) is formed when it loses an electron.
Atomic number is the total number of protons and electrons in a neutral atom.
From the information
Protons = 14
electron = 18
Net Charge = no of proton - no of electron
= 14 - 18 = -4
Mass number = 14 + 15 = 29
Thus, the chemical symbol = 
For ion with 27 proton, 32 neutrons and 25 electrons
Net charge = 27 - 25 = +2
Mass number = 27 + 32 = 59
Thus, the chemical symbol = 
3. Plasma
- indefinite shape & volume
- affected by magnetic and electric field
- drift and flow freely
4. Liquids have fixed volume meaning packed tighter together as gases do not have fixed shape or volume .
D would be correct
Answer:
NaCl.
Explanation:
In the solution, ZnSe ionizes to
and
. Following reaction represents the ionization of ZnSe in solution -
⇄ 
As we want to increase the solubility of ZnSe, we must decrease the concentration of dissociated ions so that the reaction continues to forward direction.
If we add NaCl to this solution, then we have
and
in the solution which will be formed by the ionization of NaCl.
Now,
in the solution will react with two
ions to form
as follows -
⇄ 
Due to this reaction the concentration of
will decrease in the solution and more ZnSe can be soluble in the solution.
Answer:
The most recent Global Burden of
Disease (GBD) study estimates that air pollution – indoor and outdoor combined – was the cause of 5.5 million premature deaths
globally in 2013. Air pollution also has further consequences on human health, leading in particular to an increasing number of
respiratory and cardiovascular diseases. Moreover, it affects crop yields and the environment, with impacts on biodiversity and
ecosystems, amongst others. These impacts have significant economic consequences, which will affect economic growth as well as welfare
Explanation: