The electronegativity of nitrogen (N) is 3.0, while the electronegativity of hydrogen (H) is 2.1. As it can be seen that nitrogen (N) is more electronegative than that of hydrogen (H),
So electron pairs are attracted towards nitrogen and thus it carries a partial negative charge and hydrogen carries a partial positive charge. The image of electron distribution is attached as follows.
Thus NH₃ is a polar molecule .
Answer:
3. Equal numbers of protons and neutrons
Explanation:
The nucleus becomes unstable if the ratio of protons to neutrons is less than 1:1 or more than 1:1.5.
The most stable nucleus has a neutron proton ratio of 1:1 which means that they can not release a neutron or a proton to decay.
Nucleus 3 is therefore the most stable.
"A contactor is a electrically controlled switch which uses an electromagnetic coil to pull in the contacts.”
"A motor starter is a contactor, plus an overload relay that will drop out the coil voltage if the motor overloads. If there is not overload relay, it is not a starter any longer, it's back to being just a contactor."
Answer:
5. Selenium, because it does not have a stable, half-filled p subshell and adding an electron does not decrease its stability.
Explanation:
Electron affinity is the amount of energy released when an isolated gaseous atom accepts electron to form the corresponding anion.
Selenium:-
The electronic configuration of the element is:-
![[Ar]3d^{10}4s^24p^4](https://tex.z-dn.net/?f=%5BAr%5D3d%5E%7B10%7D4s%5E24p%5E4)
Arsenic:-
The electronic configuration of the element is:-
![[Ar]3d^{10}4s^24p^3](https://tex.z-dn.net/?f=%5BAr%5D3d%5E%7B10%7D4s%5E24p%5E3)
The 4p orbital in case of arsenic is half filled which makes the element having more stability as compared to selenium.
Thus, selenium has higher electron affinity because adding electron does not decrease the stability as in case of arsenic.
Answer:
1.Very good electrical conductivity :<u> Metals</u> (Decreacing order of conductivity)
- <em>Silver > Copper > Gold > aluminium</em>
2. Amphoteric <u>: Metal elements</u>
- <em>Beryllium , Aluminium , Zinc </em>,
3.Gaseous at room temperature: mostly <u>Nobel gases elements</u> and some non - metal elements.
- <em>Helium ,neon , argon , krypton , fluorine , Oxygen , nitrogen</em>
4.Solid at room temperature:<u> Mostly Metals</u> (few non-metals, metalloid elements)
- <em>Metals (Sodium , potassium , calcium , gold are solid)</em>
<em>Non- metals(Carbon ,Boron )</em>
<em>Metalloids(antimony)</em>
<em>5.</em> Brittle <em>: </em><u>non - metals </u>(can't be rolled into wires)
<em>Hydrogen , carbon , sulfur , phosphorus</em><u> </u>
Explanation:
