Unit 1: All About Atoms Lesson 1.1: Parts of an atom Do Now: By the end of today, you will have an answer to: How do we determine the number of subatomic particles in an atom? 1. A neutron has a charge of (1) +1 (3) 0 (2) +2 (4) -1 2. Which particle has the least mass? (1) Alpha particle (3) neutron (2) Beta particle (4) proton 3. The elements on the Periodic Table are arranged in order of increasing (1) Atomic number (2) Mass number (3) Number of isotope (4) Number of moles Parts of an atom: REFRESHER! An atom is the smallest form of matter we can have. An atom is ELECTRICALLY NEUTRAL WORDS THEY THROW AT YOU: Electrically neutral Nuclear charge Subatomic particle Nuclei 1
Subatomic particles Mass Charge Location PROTONS NEUTRONS ELECTRONS Try These! 1. The mass of 12 protons is approximately equal to (1) 1 atomic mass unit (2) 12 atomic mass unit (3) the mass of 1 electron (4) the mass of 12 electrons 2. A proton has a charge that is opposite the charge of (1) an alpha particle (2) a neutron (3) an electron (4) a positron 3. Which two particles each have a mass approximately equal to one atomic mass unit? (1) Electron and neutron (2) Electron and proton (3) Proton and electron (4) Proton and neutron 4. Which subatomic particles are located in the nucleus of a neon atom? (1) Electrons and positrons (2) Electrons and neutrons (3) Protons and neutrons (4) Protons and electrons Counting subatomic particles: How to figure out PROTONS PROTONS AND NEUTRONS NEUTRONS ELECTRONS Look at PRACTICE: Element # of protons # of neutrons # of electrons Charge of nucleus C Charge of atom N Au F Cl 2
5. The total mass of the protons in an atom of gold-198 is approximately (1) 79 atomic mass units (2) 119 atomic mass units (3) 198 atomic mass units (4) 277 atomic mass units 6. What is the total charge of the nucleus of a carbon atom? (1) -6 (3) +6 (2) 0 (4) +12 8. Which statement correctly describes the charge of the nucleus and the charge of the electron cloud of an atom? (1) The nucleus is positive and the electron cloud is positive. (2) The nucleus is positive and the electron cloud is negative. (3) The nucleus is negative and the electron cloud is positive. (4) The nucleus is negative and the electron cloud is negative. 7. What is the mass number of an atom that has six protons, six electrons, and eight neutrons? (1) 6 (3) 14 (2) 12 (4) 20 QUICK CHECK: Why do we know the total number of protons and the total number of electrons based on the atomic number of an atom? Isotopes: ISOTOPE NOTATION: How many different ways can we use notation to represent gold (Au) with an atomic mass of 198? Don t forget MAP!!! 3
CW #1: Parts of an atom/ Counting subatomic particles 1. Which diagram represents the nucleus of an atom of? 10 points 5. Which particle has a mass that is approximately the same as the mass of a proton? (1) An alpha particle (2) A beta particle (3) A neutron (4) A positron 2. A student constructs a model for comparing the masses of subatomic particles. The student selects a small, metal sphere with a mass of 1 gram to represent an electron. A sphere with which mass would be most appropriate to represent a proton? 6. Compared to an atom of phosphorous-31, an atom of sulfur-32 contains (1) One less neutron (2) One less proton (3) One more neutron (4) One more proton 7. An atom has an atomic number of 9, a mass number of 19, and an electrons configuration of 2-6-1. What is the total number of neutrons in this atom? 8. The table below gives information about the nucleus of each of four atoms. 3. What is the mass number of a carbon atom that contains six protons, eight neutrons, and six electrons. (1) 6 (3) 14 (2) 8 (4) 20 4. In an atom of argon-40, the number of protons (1) Equals the number of electrons (2) Equals the number of neutrons (3) Is less than the number of electrons (4) Is greater than the number of electrons How many different elements are represented by the nuclei in the table? (1) 1 (3) 3 (2) 2 (4) 4 Base your answers to questions 9 and 10 on the information below, which describes the proposed discovery of element 118. In 1999, a nuclear chemist and his team announced they had discovered a new element by crashing krypton atoms into lead. The new element number 118 was assigned the name ununoctium and the symbol Uuo. One possible isotope of ununoctium could have been Uuo-291. However, the discovery of Uuo was not confirmed because other scientists could not reproduce the experimental results published by the nuclear chemist and his team. In 2006, another team of scientists claimed that they produced Uuo. This claim has yet to be confirmed. Adapted from Discover, Jan 2002 9. What would be the total number of neutrons present in theoretical atom of Uuo-291? 10. What would be the total number of electrons present in a theoretical atom of Uuo-291? 4
HOMEWORK #1: (20 points) Put the following terms on the glossary sheets provided: Neutron Proton Electron Charge Atom Subatomic Particle Atomic number Mass number Nucleus/ nuclei Isotope Class Example: Vocabulary Word Working Definition My Definition or Example Picture Neutron 5
Exit Ticket Quiz 1.1: Parts of an atom/ Counting subatomic particles 1. Which two particles have opposite charges? (1) An electron and a neutron (2) An electron and a proton (3) A proton and a neutron (4) A proton and a positron 3 points 2. Each diagram below represents the nucleus of a different atom. Which diagrams represent nuclei of the same element? (1) D and E, only (2) D, E, and Q (3) Q and R, only (4) Q, R, and E 3. The nucleus of one boron atom has five protons and four neutrons. a) Determine the total number of electrons in the boron atom. b) Determine the total charge of the boron nucleus. Exit Ticket Quiz 1.1: Parts of an atom/ Counting subatomic particles 1. Which two particles have opposite charges? (1) An electron and a neutron (2) An electron and a proton (3) A proton and a neutron (4) A proton and a positron 3 points 2. Each diagram below represents the nucleus of a different atom. Which diagrams represent nuclei of the same element? (1) D and E, only (2) D, E, and Q (3) Q and R, only (4) Q, R, and E 3. The nucleus of one boron atom has five protons and four neutrons. a) Determine the total number of electrons in the boron atom. b) Determine the total charge of the boron nucleus. 6