Tiêu đề EDX Topic 3 atomic & periodic table .pdf ✅

Topic 2 1 Atomic Structure & Periodic Table
Topic 3 2 Atom: It is the smallest building unit of matter, that can't be broken down further by chemical means. Element: It's a substance made up of atoms with the same atomic number. It cannot be split up into anything simpler by chemical means. Molecule: It’s a group of 2 or more atoms chemically joined together. Diatomic Molecule: A molecule made of 2 atoms chemically joined together. e.g. H2, O2, N2, F2, Cl2, Br2, I2 and At2 To sum up, Atoms are made up of 3 subatomic particles: Protons, Neutrons and Electrons. Protons and Neutrons in the center of the atom in the nucleus. Electrons in energy shells around the nucleus. Atoms are electrically neutral (have overall charge = zero) because number of positive protons = no. of negative electrons Protons and electrons are the only charge particles in an atom Note!
Subatomic Particle Mass Charge Proton 1 +1 Neutron 1 0 Electron 1/1840 -1 Z Atomic Number & Mass Number X Mass No. A Atomic No. Mass Number (Nucleon Number): it is the number of proton and neutrons inside the nucleus of an atom. Atomic Number (Proton Number): it is the number of protons inside the nucleus of an atom. Symbol of Element No. of Protons = 1 No. of Electrons = 1 No. of Neutrons = 1-1 = 0 No. of Charged Particles = 2 No. of Neutrons = Mass Number - Atomic Number No. of Protons = 8 No. of Electrons = 8 No. of Neutrons = 16-8 = 8 No. of Charged Particles = 16 Topic 3 3
Isotopes Isotopes They are different atoms of the same element having the same proton number and different mass number due to different neutron number. Explain Why? Isotopes of the same element have the same chemical properties Because they have the same number of electrons, therefore same electronic configuration. Suggest Why? The relative atomic mass of Chlorine is not a whole number Because Chlorine has isotopes, its the average mass of its isotopes. Topic 3 4