BrainPOP: Atomic Model
Using ____________________ means, scientists have been able to construct different models of the __________________. The atomic model has taken years and years to build and people still tweak it now and again, hopefully making it more accurate.
1802- At the beginning of the 19 th century, Englishman ______________________ built an atomic model called the “______________________________________.”
According to his theory, each type of _____________________ is made of only one type of __________________________. Also each type of atom could be put together into a group called an ______________________- and every atom of a given element was ______________________________. For example, gold atoms make
_____________ and iron atoms make _________________, and so on. Dalton also believed that atoms could not be ________________________, divided into smaller parts, or ______________________________.
1897- About 100 years after Dalton, British scientists ______________________ discovered the _________________________. Thompson stated that negatively charged electrons must be stuck all throughout a positively charged area. Think of it like the atom is cookie dough and the _______________________ are chocolate chips.
The discovery of electrons was a big deal. But it left some bi questions- what were the positive particles holding those electrons in place?
1909- In 1909, a New Zealand born British scientist named ___________________
______________________ and his team set out to answer some of these questions.
After performing in depth experiments using gold foil, Rutherford determined that a gold atom must have some very small ______________________ charged mass. He named this mass the ______________________. He called the positively charged nucleus particles ________________________, and said that the
__________________________ were scattered in ____________________ around the nucleus.
James Chadwick, a student of Rutherford’s, found new particles in the nucleus that weren’t affected by an electric field at all. Chadwick called these uncharged particles
_____________________________.
Also in the early 20 th century, scientists discovered that electrons are arranged in energy levels. The lower energy levels are closer to the ___________________ and can hold just a few _________________________. The higher energy levels are farther from the nucleus and can hold more _____________________________.
Electrons are so small and ____________________ that their energy levels are not neat planet-like orbits around the nucleus. Instead, they exist in a region called the electron cloud. The atomic model is constantly evolving as scientists discover more and more about what makes the universe tick.

BrainPop: Atoms
Air, water, pants, leaves, robots, and humans are all made up of ________________!
The Periodic Table of Elements shows and predicts every known ________________ in the universe- oxygen, iron, lead, and so on. These elements are all made of
____________________. Around 2400 years ago, a Greek guy named
______________________________ argued that everything in the world was made up of particles so small that they could not be cut in half. He called these tiny things “_______________” from the Greek work “atomos,” which means
“_____________________.”
In the 1800s, another guy named ____________________________________ refined the idea with his theory that atoms are the smallest particle of an
_________________ that retains its chemical __________________________.
That means if you break apart an atom of an element like carbon, it’s __________ carbon any more.
Atoms are made up of even tinier __________________________ particles called
__________________, ___________________, and ___________________.
The atom’s center, or _________________, is a cluster of protons and neutrons.
Protons have a ___________________ electrical charge, and neutrons have
______ electrical charge. The atom’s nucleus is held together by the strong force, which keeps the positively charged protons from repelling each other. The nucleus is surrounded by a cloud of ______________________ moving near the speed of light. The electrons have a _________________________ charge that attracts them to the protons, and they “live” in shells representing different
_________________________________.
On the periodic table, atoms are organized by their _______________________, which is really their number of ______________________ or
__________________. You can also find the atomic mass here, as well as the element’s symbol. The difference of a few little protons, electrons, or neutrons can produce such a variety of _____________________ with completely different
________________________. Different types of atoms can bond together to make __________________________. Water is a molecule. It’s two atoms of
___________________, and one atom of __________________, or H
2
O for short!
You would not believe how small atoms are. It would take nearly 10 million just to cross this dot. And the _________________ of the atom itself is even more ridiculous. If the nucleus was the size of an apple, the _______________________ would be five whole football fields away! That means all matter in the universe is mostly __________________ space!