Answer:
Answer in explanation
Explanation:
a. Boron , element 5
Helium has 2 electrons, add to the other 3 to give 5.
Other group members are : Aluminum Al, Gallium Ga, Indium In , Thallium Tl and Nihonium Nh
b. Sulphur, element 16
Neon is 10 , add other 6 electrons to make 16
Other group members are: Oxygen O, selenium Se , Tellurium Te and Polonium Po
c. Lanthanum, element 57
Xenon is 54, add the other 3 electrons to give 57.
Other elements in group : Scandium Sc , Yttrium Y , Actinium Ac, Lutetium Lu and/or Lawrencium Lr
Answer:
the answer is 7 which is the atomic number of nitrogen
Explanation:
Al+Na=24
24/Oxygen (8) =3
3x rounded atomic mass of Ne (3x20) = 60
60+ 20 (# of neutrons in K)=80
80-30 (# of electrons in zinc)= 50
50/25 (the atomic number of Mn)=2
2x9 (number of protons in F)= 18
18+24 (atomic mass of Mg)=42
42/6 (number of neutrons in boron)=7
7 is the atomic number of Nitrogen (N)
Answer:
Ea=5.5 Kcal/mole
Explanation:
Let rate constant are 
and 
at temperature 
and 
By using Arrhenius equation at two different two different temperature,
By putting value of R=2 cal/mole.K
By rounding off upto 2 significant figure;
Answer:
407pm is the edge length of the cubic unit cell
Explanation:
In a Face-centered cubic unit you can use Pythagoras theorem to relate edge length with atomic radius (As you can see in the picture), thus:
e²+e² = (4r)²
2e² = 16r²
e = √8 r
If the atomic radius of the atom is 144pm:
e = √8 ×144pm
e = 407ppm
407pm is the edge length of the cubic unit cell
A model of an atom is much bigger than a real atom, but the model of the solar system is obviously much smaller.
