Answer:
4.has gained two electrons
Explanation:
There exist electrovalent bonding the compound MgS . In electrovalent bonding, there is a transfer of electrons from the metal to non-metal.
Magnesium atom has an atomic number 12 and its electron configuration is 2,8,2
Sulfur atom , a non-metal has atomic number of 16 and its electron configuration = 2,8,6
This means that magnesium as a metal needs to loose two electrons from its valence shell to attain its stable structure.Also sulfur requires two more electron to achieve its octet structure.
Hence a transfer of electrons will take place from magnesium atom to sulfur atom, sulfur gaining two electrons.
U=10 m/s
v=30 m/s
t=6 sec
therefore, a=(v-u)/t
=(30-10)/6
=(10/3) ms^-2
now, displacement=ut+0.5*a*t^2
=60+ 0.5*(10/3)*36
=120 m
And you can solve it in another way:
v^2=u^2+2as
or, s=(v^2-u^2)/2a
=(900-100)/6.6666666.......
=120 m
That's unaccelerated motion,
and constant velocity.
