Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...

Some of them quickly combined to make helium (atomic number 2). These two elements still make up 98% of the universe, and they are the primary ingredients in stars. A pioneering astronomer named ...

Next, the atomic number "2" "helium(He) ". Helium is the second lightest gas after hydrogen, which is used for balloons. It is a very stable gas which does not react with other atoms because it is ...

For example hydrogen has the atomic number of one, helium two, lithium three etc. The first energy level (the one nearest the nucleus) can hold a maximum of 2 electrons with the others being able ...

Dalton, considered the father of modern atomic theory ... Atoms combine only in small, whole-number ratios like 1:1, 1:2, 2:3, etc. Atoms can not be created or destroyed. Dalton's symbols were ...

The atomic number of oxygen is listed as 8. This means oxygen has 8 protons in its nucleus. Example 2: Sodium Sodium is a metal commonly found in table salt. To find its atomic number: Look at the ...

Atoms are made up of protons, neutrons, and electrons. The number of protons in one atom of an element is its atomic number. Hydrogen has one proton, so its atomic number is one. Carbon atoms have ...