Chapter 2. Structure of Atom Level X.pptx

Structure Atom

1. Chapter 2 Structure of Atom and Nanotechnology Here is where your presentation begins X Grade SMA ABBS SURAKARTA 2024/2025

2. Learning Objectives Understand the development of atomic theory as well as atomic structure and its applications in nanotechnology.

3. You could use four columns, why not? Electron Atom Atom Charge Muatan Elektron GLOSSARY Nucleus Proton Proton Neutron Neutron Inti atom Particle Partikel Shell Kulit

4. What is the smallest material contained in these 2 objects?

5. Evolution of Atomic Theory 01

6. Atomic theory timeline 01 DALTON 1803 02 THOMSON 1804 03 RUTHERFORD 1909 04 BOHR

7. 1. DALTON’S ATOMIC THEORY John Dalton is often known as the father of atomic theory. He proposed a theory of the atom in 1803. John Dalton believed that: All matter is made of atoms Atoms were solid spheres Atoms within an element are the same. Atoms from different elements are not. Atoms couldn’t be further broken down Atoms are rearranged during a chemical reaction but are not lost. This is the Law of Conservation of Mass.

8. 2. THOMSON’S ATOMIC THEORY Thomson also knew that atoms are neutral in electric charge, so he asked the same question: How can atoms contain negative particles and still be neutral? He hypothesized that the rest of the atom must be positively charged in order to cancel out the negative charge of the electrons. He presented the atom as being similar to a plum pudding, mostly positive in charge (the pudding) with negative electrons (the plums) scattered through it. John Dalton discovered atoms in 1804. He thought they were the smallest particles of matter, which could not be broken down into smaller particles. It wasn’t until 1897 that a scientist named Joseph John (J.J.) Thomson discovered that there are smaller particles within the atom.

9. 3. RUTHERFORD’S ATOMIC THEORY While most particles did pass through, some were deflected more than Rutherford expected, and some were deflected backwards, showing that the plum pudding model could not be correct. Rutherford developed a theory where the atom had a tiny positively charged nucleus in the centre with a cloud of negative electrons surrounding it. In 1909, Ernest Rutherford and two of his students conducted the now infamous gold foil experiment. They fired positively charged alpha particles at a very thin sheet of gold. If the plum pudding model were correct, the particles would either pass through the sheet of gold or be very slightly deflected as the charge was thought to be spread through the atom. Gold was chosen as it can be made very thin

10. 4. BOHR’S ATOMIC THEORY Bohr was part of a group of scientists interested in a new field of science called quantum mechanics. Quantum mechanics is the study of how atomic particles exist and interact with each other. Bohr was particularly interested in the energy possessed by electrons. Scientists were beginning to understand more about energy and subatomic particles. Based on this, Bohr suggested that electrons orbit the nucleus along specified paths. He called these electron shells . The electron shells are labelled using either letters (K, L, M, N, O, P, Q) or quantum numbers (n=1 to n=7). Rutherford’s planetary model explained a lot. But it didn’t answer some questions that scientists still had. They wondered where the electrons actually were and could their location be predicted? They also wondered why the orbiting electrons didn’t lose energy and crash into the nucleus. Luckily, Danish scientist Niels Bohr was trying to find those answers.

11. Atomic Structure 02

12. 1. Atomic Number & Mass Number A X Z Jupiter Mass number Atomic Symbol Jupiter Atomic number

13. X as the symbol A as mass number Z as atomic number The atomic number of a neutral atom equal with the number of protons and the number of electrons. 1 The atomic symbol has 3 part 2 3

14. Answer this question Find the Mass number whose atomic number is 15 and the number of neutrons present is 15. When an atom is written , please determine number of protons, neutrons, and electrons!  

15. 2. How Many Electrons in The Ion?

16. 3. Isotopes, Isobars, Isotones

17. Thank You