66 points! which is true about the four atoms shown in figures a, b, c, and d?

a.
a and b are the same element. c and d are the same element, and a different element than a and b.

b.
a, b, and d are different elements, while c is an isotope of b.

c.
a, c, and d are different elements, while b is an isotope of d.

d.
b, c, and d are different elements, while a is an isotope of c.

-- A and B are the same element.

-- C and D are the same element, and a different element than A and B.

This is choice-A .

It all comes down to counting the number of protons in the nucleus of each atom.

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explanation:

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the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.