Answer: 68.
Explanation:
The atomic number is the number that idenfities an element.
The atomic number is the number of protons of an element.
Every element has a different number of protons.
The elements are arranged in the periodic table as per their atomic number (number of protons).
The first element is hydrogen (H), its atomic number is 1, and it has 1 proton.
The second element is helium (He), its atomic number is 2 (it has 2 protons)-
Those two elements form the first period (row) of the periodic table.
The second row (period) has the elements Li, Be, B, C, N, O, F and Ne, whose respective atomic numbers (number of protons are) 3, 4, 5, 6, 7, 8, 9, and 10, respectively.
And so, you may idenfity each of the 118 elements known, with a different atomic number (number of protons).
These could all go either way, hardness and other special properties are what I'm guessing would be the most accurate in determining the kind of material.
luster, cleavage, streak, and color can all be affected by other factors. but I guess cleavage would also be accurate. so I guess hardness special properties and cleavage would be the most reliable.
The Octet rule is a general rule of thumb that applies to most atoms. Basically, it states that every atom wants to have eight valence electrons in its outermost electron shell.
It depends, for example, it is quite important to know the Kelvin scale (i.e 0 degrees Celsius is 273 K and -273 degrees Celsius is 0 K ) when dealing gases. But I don't know other situations where you would need to know other temperature scales.
Hope this helps and also if you are using Fahrenheit 1 Fahrenheit is -17.22 degrees Celsius
