structure of atom

atomic structure, types of states of matter, temperature.

1. MEDICAL PHYSICS

2. Introduction The course covers the knowledge and application of Medical Physics in the field of Physical Therapy. Medical Physics covers application of basic concepts, laws, theories of Physics in health care and Physiotherapy. Construction of the instruments used in Electrotherapy. Understand the Basic concepts of Physics of currents, production and physiological and chemical effects. In medical physics we study the basic principal of physics applied on modalities used in physiotherapy.

3. Table of content Structure of Atom States of matter Formation of compound Types of elements Transmission of heat Formation of compound

4. Structure of Atom

5. Atom John Dalton; matter is composed of atom. J.J Thompson; structure of atom. Rutherford; discovery of Nucleus. Neil Bohr; electronic arrangement Quantum Physics; atom consist of many sub atomic particles.

6. Atom Atom, tiny basic building block of matter. All the material on Earth is composed of various combinations of atoms. An atom consists of a cloud of electrons surrounding a small, dense nucleus of protons and neutrons. Atoms are the smallest particles of a chemical element that still exhibit all the chemical properties unique to that element. Diameter of atom is 10-10 m.

7. Structure of atom

8. Nucleus

9. Nucleus An atom consists of a cloud of electrons surrounding a small, dense nucleus of protons and neutrons. The nucleus contains nearly all of the mass of the atom, but it occupies only a tiny fraction of the space inside the atom. The diameter of a typical nucleus is only about 1 × 10-15 m to 1 × 10-14 m.

10. Nucleus Central part of an atom is nucleus. It has two particles proton and neutron (nucleon). These are held together by nuclear forces. It has positive charge.

11. RUTHERFORD’S MODEL   RUTHERFORD’S MODEL Most of the positively charged “bullets” passed right through the gold atoms in the sheet of gold foil without changing course at all. Some of the positively charged “bullets,” however, did bounce away from the gold sheet as if they had hit something solid . He knew that positive charges repel positive charges.

12. Proton Proton (p+) was discovered by E.Goldstein . Proton has 1 unit mass. Protons have a positive electrical charge of 1.602 x 10-19 coulomb. This charge is equal but opposite to the negative charge of the electron. A proton’s mass is about 1,840 times the mass of an electron. Protons carry a positive charge of +1, exactly the opposite electric charge as electrons. The number of protons in the nucleus determines the total quantity of positive charge in the atom.(atomic number).

13. Neutron Neutron (n) was discovered by Sir James Chadwick. The neutron is slightly heavier than a proton and 1,838 times as heavy as the electron. Neutron, electrically neutral elementary particle that is part of the nucleus of the atom. The neutron is about 10-13 cm in diameter and weighs 1.6749 x 10-27 kg

14. Atomic mass / Atomic number The sum of protons and neutrons is called atomic mass. Example Carbon12. The number of proton in an atom is called atomic number. Example carbon 6.

15. Isotopes In certain elements number of neutrons are different in their nuclei. These are called isotopes. Example carbon 12, 13, 14. Isotope, one of two or more species of atom having the same atomic number, hence constituting the same element, but differing in mass number. The nucleus, and mass number is the sum total of the protons plus the neutrons in the nucleus, isotopes of the same element differ from one another only in the number of neutrons in their nuclei.

16. ISOBARS The total number of nucleons is the same in the atoms of this pair of elements. Atoms of different elements with different atomic numbers, which have the same mass number, are known as isobars.

17. Shells

18. Shells The electrons are arranged in definite energy shell or orbits around the nucleus called principal quantum shell. These are seven. K,L,M,N…… Octets rule. 2n2. Each shell is divided into 4 sub shells, s,p,d,f . The electrons fill lowest shell first.

19. Electrons Electrons (e-) were discovered by sir. J.J. Thomson.Electrons are tiny, negatively charged particles around the nucleus of an atom. Each electron carries a single fundamental unit of negative electric charge–1.602 x 10-19 coulomb and has a mass of 9.109 x 10-31 kg. The electron is one of the lightest particles with a known mass.

20. Electrons These are responsible for physical and chemical activities of an atom. A strong force of attraction is present between electron and nucleus. It obeys the inverse square law. F  1/d2

21. Bound electrons Valance electrons Electrons which are close to the nucleus are tightly bound. These are called bound electrons. As the number of orbit increases, the force of attraction between electrons and nucleus is weak. As a result these are free electrons.

22. Ions Positive ion cation Negative ion anion If an atom loses on electron it becomes positive ion. Example sodium ion If an atom gains on electron it becomes negative ion. Example chlorine ion

23. States of matter

24. Matter Every thing that have weight and occupy space is called matter. Cohesive forces are attractive forces between the molecules of matter. Kinetic forces are movement of the molecules.(vibrations)

25. States of matter

26. Solids Matter which have fix shape and fix volume. Cohesive forces are strongest. Kinetic forces are weak. Just about there mean position. Strong m.p and b.p . Example wood. Iron. Glass.etc

27. Liquids Matter having fix volume but not fix shape. They take the shape of container. Cohesive forces weak Kinetic forces are strong. Moderate m.p and b.p . Example water mercury.

28. Gases Matter which do not have fix shape and fix volume. Cohesive forces weakest. Kinetic forces are strongest.(randomly) Example different gases oxygen nitrogen etc

29. Plasma It is considered as forth state of matter. It consist of atoms, Ions, free electron, etc. It is in the form of semi solid. Universe is made up of plasma.

30. Types of Elements

31. Types of elements Conductors Insulators

32. Conductors Elements which allow passage of heat and electricity are called conductors. These elements have free electrons in their outer most shell. These electrons allow flow of heat. All metals are good conductor. Cupper, gold, iron, etc

33. Insulators elements which do not allow passage of heat and electricity are called insulators. These elements do not have free electrons in their outer most shell. Outer shells are completely filled. All non metals are insulators. Wood, carbon, glass, etc

34. Conductivity of Selected Materials Conductors Fair Conductors Insulators Copper Water with dissolved minerals Rubber Aluminum Moist Air Wood Iron Human Body Plastic Mercury Carbon Pure Water Other metals Soil Metal oxides such as rust

35. Transmission of Heat

36. Heat It is a form of energy that is transferred from one body to the other body as a result of temperature difference.

37. Transmission of heat

38. Transmission of heat Heat has ability to transfer from area of higher temperature to area of lower temperature. It is called temperature.

39. Conduction Transmission of heat in solids is called conduction. If one end of a metal rod is heated, it causes increase in temperature at that end. Kinetic forces of molecules increase. It conduct the heat to the other end.

40. Convection Transmission of heat in liquids and gases is called convection. When fluid in a pot is heated, kinetic energy increases, molecules moves away from each other, area become less dense, the more fluid come to take its place. The whole process continues until the temperature of liquid become equal.

41. Radiations Transmission of heat between air and vacuum is called radiation. Transmission of heat from sun to earth is by radiations. Heat in vacuum is transmitted by electromagnetic radiations. As a substance is heated, it cause electron to move the higher energy shell. When the electron moves back to lower energy shell. Energy is released in the form of heat.

42. Formation of Compounds

43. Compounds Ionic compound Covalent compound These compounds are formed by the complete transfer of electrons. Example NaCl These compounds are formed by the mutual sharing of electrons. Example CH4

44. THANKS

45. What subatomic particle has a mass of one atomic mass unit? a) proton b) neutron c) electron d) more than one of the above

46. True or false: All isotopes are radioactive. a) True b) False

47. Cations have: a) Positive charge b) Negative charge c) No charge d) It is impossible to predict the charge on a cation

48. Strongest cohesive forces are present in solids Liquids Gases All

49. Heat passes from vacuum by method of Conduction Convection Radiation All