How does atomic radius change from left to right across a period in the periodic table?

a. it first decreases, then increases.
b. it tends to decrease.
c. it first increases, then decreases.
d. it tends to increase.

Option (b) is the correct answer.

Explanation:

When we move from left to right across a period in a periodic table then there will occur a decrease in size of the atoms because electrons are added to the same shell.

As a result, nucleus tends to pull the electrons towards itself due to which shrinkage in the size of atoms tends to occur.

Thus, we can conclude that atomic radius tends to decrease from left to right across a period in the periodic table.

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j