THE ATOMIC STRUCTURE OF MATTER FÍSICA Y QUÍMICA 3º DE E.S.O. UNIT 1: THE ATOMIC STRUCTURE OF MATTER FQ3ESO_U1_2: SUBATOMIC PARTICLES U.1_2 d1

2.7. Estructura atómica. Isótopos. Modelos atómicos.. Bloque 2. La materia 2.7. Estructura atómica. Isótopos. Modelos atómicos.. Criterios de evaluación C.E.2.6. Reconocer que los modelos atómicos son instrumentos interpretativos de las distintas teorías y la necesidad de su utilización para la comprensión de la estructura interna de la materia. CMCT, CAA. Estándares de aprendizaje evaluables EE.A.2.6.1. Representa el átomo, a partir del número atómico y el número másico, utilizando el modelo planetario. E.A.2.6.2. Describe las características de las partículas subatómicas básicas y su localización en el átomo. E.A.2.6.3. Relaciona la notación AZX con el número atómico, el número másico determinando el número de cada uno de los tipos de partículas subatómicas básicas. C.E.2.7. Analizar la utilidad científica y tecnológica de los isótopos radiactivos. CCL, CAA, CSC E.A.2.7.1. Explica en qué consiste un isótopo y comenta aplicaciones de los isótopos radiactivos, la problemática de los residuos originados y las soluciones para la gestión de los mismos. U.1_2 d2

Characteristics of atoms An element is matter that is made up of one type of atom. An atom is the smallest piece of matter that still has the properties of the element. U.1_2 d3

Characteristics of atoms C, Al, Ne, and Ag are all chemical symbols for different elements. Chemical symbols make writing names of elements easier. Chemical symbols are either one capital letter or a capital letter plus one lowercase letter. C U.1_2 d4

Atomic Components Subatomic particles are particles that are smaller than the atom. Atoms are made up of protons, neutrons, and electrons. Protons are particles with an electrical charge of +1. Neutrons are particles with no electrical charge. Electrons are particles with an electrical charge of –1. U.1_2 d5

Atomic Components Protons and neutrons have approximately the same mass. One proton has the same mass as 1836 electrons. If an electron was the size of a coin … … a proton would have the mass of a large bowling ball! U.1_2 d6

Atomic Components The nucleus is the small, positively charged center of the atom. It is made up of protons and neutrons. The nucleus is surrounded by a cloud containing electrons. U.1_2 d7

Atomic Components 99.999999999999% of an atom's volume is just empty space! 5.3 kilometers 65.5 m 30.48 cm 2.6 kilometers Nucleus = 1/10,000th size of the atom U.1_2 d8 (Pluto is a dwarf planet)

Inside the heart of a nucleus U.1_2 d9

Atoms of different elements differ in the number of protons they contain. Atoms of different elements have a different number of protons. All atoms with one proton are hydrogen atoms. For example, all atoms with 11 protons are sodium atoms. U.1_2 d10

The number of protons tells you what type of atom you have and vice-versa. For example, every carbon atom has six protons. Also, every atom with six protons is carbon U.1_2 d11

The atomic number (Z) of an element is the number of protons in an atom of the element. Since carbon has six protons, the atomic number of carbon is 6. U.1_2 d12

The mass number of an atom (A) is the sum of the number of protons and the number of neutrons in the nucleus of the atom. A = Z + N = 6 protons + 6 neutrons = = 12 nucleons U.1_2 d13

protons, the atomic number of carbon is Z = 6. Since carbon has six protons, the atomic number of carbon is Z = 6. If the atom is neutral the number of electrons is 6 U.1_2 d14

Atomic number and mass number A = Mass number = = number of nucleons = = number of protons + number of neutrons Z = Atomic number = number of protons A = Z + N N = Neutron number U.1_2 d15

Número atómico y número másico Z = A = Z + N U.1_2 d16

How is the number of neutrons found How is the number of neutrons found? If you know the mass number and atomic number of an atom, you can find the number of neutrons it contains. number of neutrons = mass number - atomic number 7 Li 3 A = Z + N N = A - Z N = A - Z = 7 - 3 = 4 neutrons U.1_2 d17

Determining the number of atomic particles U.1_2 d18

Determining the number of atomic particles U.1_2 d19

Isotopes Isotopes of elements occur when atoms have the same atomic number (Z) but different numbers of neutrons in the nucleus. Li-6 Li-7 Li-8 The number of neutrons in an atom does not affect the way an element behaves chemically, but it does affect the way it behaves physically U.1_2 d20

Isotopes C-12 C-13 C-14 CARBON 12 CARBON 13 CARBON 14 Some isotopes are radioactive or unstable and change into other element. U.1_2 d21

Isotope symbols U.1_2 d22

Isotope symbols U.1_2 d23

Isotopes C-14 is being constantly formed in the upper atmosphere by cosmic ray interactions with nitrogen. All living things have the same amount of C-14. The pharaoh below feeded on living things when he was alive, and incorporated the C-14 into his body. U.1_2 d24

Isotopes When the pharaoh was dead he could not continue feeding on living things and did not incorporate the C-14 into his body any more U.1_2 d25

Isotopes Once an organism dies, the relative amount of C-14 declines by 50% for every 5730 years - the half-life of C-14. By measuring the relative amount of C-14 in the mummy, compared with modern material, the age can be calculated. U.1_2 d226

What do we do with the radioactive waste? Isotopes are used to obtain energy What do we do with the radioactive waste? U.1_2 d27

What do we do with the radioactive waste? Isotopes are used to obtain energy… but not only What do we do with the radioactive waste? U.1_2 d28