The diameter of a hydrogen atom is about 5×10^-11 meter. Suppose 8.4×10^8 hydrogen atoms were arranged side by side in a straight line. Multiply these numbers to find the length of this line of atoms. What is the length in scientific notation?

42×10^−3 meter

0.042 meter

4.2×10^−2 meter

4.2×10^−3 meter

A hydrogen atom's diameter in metres is

5.3×10
−11
m
.





How many hydrogen atoms could fit in a line of
0.047metres?

To find the length of the line of hydrogen atoms, we need to multiply the diameter of a single atom (5×10^-11 meter) by the number of atoms (8.4×10^8).

Multiplying these numbers, we get:

(5×10^-11 meter) × (8.4×10^8) = (5×8.4) × (10^-11 × 10^8)

= 42 × 10^-3 meter

Therefore, the length of the line of hydrogen atoms is 42×10^-3 meter, which can also be expressed as 4.2×10^-2 meter in scientific notation.

So, the correct answer is 4.2×10^−2 meter.

To find the length of the line of hydrogen atoms, we need to multiply the diameter of a single hydrogen atom by the number of atoms arranged in a straight line.

Diameter of a hydrogen atom = 5×10^-11 meter
Number of hydrogen atoms arranged side by side = 8.4×10^8

To multiply these numbers, we can use the rules of scientific notation:

(5×10^-11) × (8.4×10^8)

When multiplying numbers in scientific notation, we multiply the coefficients and add the exponents:

5 × 8.4 = 42
10^-11 × 10^8 = 10^(-11+8) = 10^-3

Therefore, the length of the line of atoms is 42×10^-3 meters.

However, the options provided are in scientific notation, so we need to convert the answer to scientific notation as well. 42×10^-3 can be written as 4.2×10^-2, which matches the answer choice:

4.2×10^−2 meter

1. 0.042

2. 0.042
3. 0.0042

I have no idea how that works. i used cymath . com to get the answer.

Nice multiplication and minus signs by the way.