Help! Chemistry?

Question

i need help for these two question
1. In what type of ratios do atom combine to form compounds?
2. how many copper atoms would you have to line up side by side to form a line 1 m long?

Answer 1

1. Small whole numbers.

2. First find the volume of a copper atom. Then, using the formula for the volume of a sphere, V = (1/6)*pi*d^3, find the diameter of a copper atom. Finally, divide 1 meter by the diameter to find the number of spheres.

Density of copper = 8.94 g/cu cm Atomic weight of copper = 63.5

[1 cu cm Cu/8.94gCu] x [63.5gCu/1 molCu] x [6.02x10^23atom Cu/1 molCu] = (63.5)/(8.94)(6.02x10^23) = 1.18 x 10^-23 cu cm/1 atomCu

The first term comes from the density. The second factor comes from the atomic weight. The grams Cu cancel, leaving cu cm/mol. The third factor comes from Avogadro's number. The moles Cu cancel, leaving cu cm/atom.

d^3 = (6)(1.18 x 10^-23)/(3.14) = 22.2 x 10^-23 = 2.22 x 10^-21
d = 1.05 x 10^-7 cm = 1.05 x 10^-9 m

That comes from rearrangement of V = (1/6)*pi*d^3 to d^3 = 6V/*pi*

Finally: 1 m/1.05 x 10^-9m = 0.952 x 10^9 atoms = 9.52 x 10^8 atoms

Answer 2

Answer from a physicist:
1. It depends on the valencies( number of free charges) of the two ions which combine to form a neutral compound molecule.
For example, Hydrogen ion (H+) has one positive free charge and positive valency one (somehow the neutral hydrogen atom has lost its electron) and Oxygen ion(O- -)has two free negative charges and negative valency two (somehow the neutral oxygen atom has has gained two electrons). They join together to form a neutral molecule of water. Two hydrogen ions join with one ion of Oxygen and the water molecule is, thus, neutral.
2.When answering questions, I do not like to spend much time on looking the information needed. So I shall give the idea only.The diameter of an atom is of the order of One Angstrom which is 10^(-8) cm or 10^(-10) m.This is actually for the hydrogen atom.I will take this value for the copper atom also, although it should much bigger. You can look it up in a table in a physical chemistry book. So the answer would be 1/10^(-10) =10^(10)atoms.
But copper atoms are not like balls and they do not touch one another.What does touching mean in case of atoms?? In terms of their outermost electrons. you cannot think atoms like balls which I did to estimate only the order o the value.

Answer 3

1) small whole numbers
2) an atom of copper has a radius of 135 pm
that´s about 0.000000000135 meters
so you would need to line up aproximately 7407407407 atoms.