Atoms, Molecules, Ions, University of Santo Tomas, PDF

ATOMS, MOLECULES, IONS Katherine Kyra D. Alonday-Lactaoen, LPT, RPh, MS Phar, CIP Master Teacher I, UST Senior High School STEM Strand © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further di...

ATOMS, MOLECULES, IONS Katherine Kyra D. Alonday-Lactaoen, LPT, RPh, MS Phar, CIP Master Teacher I, UST Senior High School STEM Strand © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education. ATOMS, MOLECULES, IONS CHAPTER 2 – Chemistry: Atoms, Molecules, Ions - Dalton’s Atomic Theory - Basic Laws of Matter - Atomic Structure - Subatomic Particles - Molecules, Ions and Isotopes - *Chemical Formulas – writing and naming © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education. Are atoms divisible? ATOM - basic unit of an element that can enter a chemical reaction. SUB-ATOMIC PARTICLES: 1. Electrons 2. Protons 3. Neutrons ATOMIC MODELS – all models hypothesizing the structure of an atom and placement of its sub-particles. 18th century (1808) – Dalton’s Atomic Theory 1. All matter is composed of atoms. 2. All atoms of a given element are identical both in mass and chemical properties. The atoms of one element is different from the atoms of all other. 3. Atoms combine in simple, fixed whole-number ratios to form compounds. 4. Chemical reactions: separation, combination, or rearrangement of atoms only. DALTON https://2ladd.com/en/2020/02/john-dalton-his-atomic-theory-model-experiments-and-discoveries/  Each atom is unique to each element. Each atom has a unique set of properties. Compounds are formed in small, whole number and fixed ratios. Compounds contain more than one element. Law of Conservation of Mass Chemical reactions do not result in their creation nor destruction of matter. © McGraw-Hill Education. 1-7 Thompson’s Cathode Ray Tube (CRT) experiment Cathode rays were deflected by the negative plate but attracted by the positive plate = ELECTRONS Electrons are more than 1000 lighter than H, and its mass is the same regardless of the element where it came from. Extended reading: Cathode Ray Tube experiment on pp. 43-44 pinterest.ph/pin/634726141213974952/ Thompson’s Plum Pudding Model The negative charges of the electrons are balanced out by the positive charges in the atoms making the atom overall neutral There are spaces between atoms. https://www.britannica.com/science/Thomson-atomic-model Rutherford’s Gold Foil Experiment Rutherford described alpha and beta rays as positive and negatively charged radiations. https://www.pinterest.ph/pin/52213676905543292/  Ernest Rutherford’s Atomic Model Most of the atom must be empty space The atom’s positive charges, are all concentrated in the nucleus The positively charged particles in the nucleus are called protons. same quantity of charge as an electron and has a mass of 1.67262 x 10-24 g https://en.wikipedia.org/wiki/Rutherford_model James Chadwick’s Beryllium experiment Neutrons - electrically neutral particles having a mass slightly greater than that of protons. https://sites.google.com/site/theapatomicmodel/james-chadwick Bohr’s Atomic Model Revised Rutherford’s atom to create a more stable model of the atom. Atoms are mostly empty space with a positively charged nucleus surrounded by electrons that travel in circular orbits. http://thehistoryoftheatom.weebly.com/niels-bohr.html Tatay ni atom si DEMOCRITUS DEMOCRITUS coined the term “atom” RECALL ☺ Si DALTON mahilig sa Atomic theory DALTON proposed the widely known atomic theory. Matakaw si THOMPSON; mahilig siya sa pudding. THOMPSON hypothesized that the atom is similar to a plum pudding model. Laging “positive” at nasa center si RUTHERFORD RUTHERFORD discovered protons; postulated that the atom is mostly empty, with a p+ filled nucleus. Duwag si CHADWICK. Di ka n’ya ipaglalaban kasi lagi syang “neutral” CHADWICK proved the existence of neutrons, which are neutral particles more massive than protons. BOHR-ring kapag “negative” lagi BOHR proved that electrons move around the atoms in rings or orbits. ACTIVITY: Practice Exercise 1 Distinguish either the discovery or the name of the scientist responsible for the scientific breakthrough. Copy the given and complete the table below: Scientist Law, Discovery, or Atomic Model 1. Sir John Dalton 2. ______________ All matter is composed of “atom/(s)” from the Greek word “atomos” meaning uncuttable. 3. Sir Joseph Proust ______________ 4. Sir Joseph John Thompson ______________ 5. ______________ Positively charged particles in the nucleus using Gold Foil experiment 6 Sir James Chadwick ______________ 7. Sir Neils Bohr ______________ Characteristics of Subatomic Particles SUBATOMIC SYMBOL MASS MASS CHARGE PARTICLE (grams) (amu) (Coulomb) electron e- 9.11x10-28 5.49 x10-4 -1.602 x 10-19 proton p+ 1.67 x10-24 1.0073 1.602 x 10-19 neutron n0 1.68 10-24 9.0087 0 What can you infer? SUB-TOPIC: Atomic Number, Mass Number and Isotopes Z = ATOMIC NUMBER - number of protons in the nucleus of each atom of an element; unique to every element (like a class number)! A = MASS NUMBER - the total number of neutrons and protons present in the nucleus; usually have decimal numbers ISOTOPES - Atoms that have the same atomic number but different mass numbers; same atomic number means they are one and the same element. Periodic Table: Standardized Exams: atomic number (Z) is the number of protons in the nucleus of each atom of an element mass number (A) is the total number of neutrons and protons present in the nucleus. All atomic nuclei contain both neutrons and protons except Hydrogen which has 1 proton but no neutron. Z atomic number = Palaging protonZ… pwede ring electronZ Z = p+ …. and sometimes, Z = e- A mass number = MAS marami kasi lahat ng nasa NUcleus A = p+ + n0 or A = Z + n0 In a neutral atom, the number of protons is equal to the number of electrons. In an ELEMENT, p+ = e- Z indicates the number of electrons in neutral atom. Let’s try this! Element A Z p+ e- n0 A 15 8 B- 6 18 Practice Exercise 2 Copy the table and complete the missing cells. Element or A Z Protons Electrons Neutrons Ion 1. A 6 18 2. B 42 24 3. C- 42 22 21 4. D2+ 10 8 19 5. E3- 27 30 ISOTOPES Atoms that have the same atomic number but different mass numbers. Same elements but different “variety”. Number of protons do NOT change. Instead, number of neutrons change in forming isotopes. ISOTOPES A 235 U 238 U X 92 92 Z Different mass numbers means: Same no. of _____ but different no. of ______. THANK YOU! TOPIC 2: ATOMS, MOLECULES, IONS ✔Dalton’s Atomic Theory ✔Basic Laws of Matter ✔Atomic Structure ✔Subatomic Particles ✔Molecules, Ions and Isotopes ❑Chemical Formulas – writing and naming © McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education.  ANSWERS TO IN-PPT EXERCISE ANSWERS: Practice Exercise 1 Scientist Law, Discovery, or Atomic Model 1. Sir John Dalton Dalton’s Atomic Theory 2. Democritus All matter is composed of “atom/(s)” from the Greek word “atomos” meaning uncuttable. 3. Sir Joseph Proust Law of Definite Proportions 4. Sir Joseph John Thompson Electrons as negatively charged particles using the Cathode Ray Tube experiment; Plum pudding model 5. Sir James Rutherford Positively charged particles in the nucleus using Gold Foil experiment 6 Sir James Chadwick Neutrons as neutral sub-atomic particles 7. Sir Neils Bohr Bohr’s atomic model where electrons orbit in concentric rings around the nucleus ANSWERS: Practice Exercise 2 Copy the table and complete the missing cells. Element or A Z Protons Electrons Neutrons Ion 1. A 24 6 6 6 18 2. B 42 24 24 24 18 3. C- 42 22 22 21 20 4. D2+ 27 10 10 8 19 5. E3- 43 27 27 30 16