Atoms and Atomic Variables

Based on the graph, which statement is FALSE? Mathematics Booster Based on the graph, which statement is FALSE? Bob is the tallest Meg is 3 inches taller than Ann Bob is 1 foot taller than Ann Each horizontal line of the y-axis equals 1 inch of height.

Based on the graph, which statement is FALSE? Mathematics Booster Based on the graph, which statement is FALSE? Bob is the tallest TRUE Meg is 3 inches taller than Ann TRUE Bob is 1 foot taller than Ann TRUE Each horizontal line of the y-axis equals 1 inch of height. It equals 3”

Objectives I will know the charges and locations of protons, neutrons and electrons in an atom I will be able to determine how many protons, electrons and neutrons are in an element and explain how to determine the number of protons, electrons and neutrons

Objectives I will know how ions form. I will be able to name ions and state their charges.

What is an atom? Atom: the smallest unit of matter that retains the identity of the substance First proposed by Democratus. Democratus was a Greek philosopher who proposed that matter was made up of tiny, indivisible particles he called “atomos” because they could not be cut.

Atomic Structure Atoms are composed of 2 regions: Nucleus: the center of the atom that contains the mass of the atom Electron cloud: region that surrounds the nucleus that contains most of the space in the atom Nucleus Electron Cloud

What’s in the Nucleus? The nucleus contains 2 of the 3 subatomic particles: Protons: positively charged subatomic particles Neutrons: neutral subatomic particles *Protons and neutrons have the same mass.

What’s in the Electron Cloud? The 3rd subatomic particle resides outside of the nucleus in the electron cloud Electron: the subatomic particle with a negative charge and relatively no mass

How do these particles interact? Protons and neutrons exist compacted in the tiny positively charged nucleus accounting for most of the mass of the atom The negatively charged electrons are small and have relatively no mass but occupy a large volume of space outside the nucleus

How do the subatomic particles balance each other? In an atom: The protons = the electrons If 20 protons are present in an atom then 20 electrons are there to balance the overall charge of the atom—atoms are neutral The neutrons have no charge; therefore they do not have to equal the number of protons or electrons

Suggestion…. Open your textbook to the page containing a periodic table of elements (132-133).

How do we know the number of subatomic particles in an atom? Atomic number: this number indicates the number of protons in an atom Ex: Hydrogen’s atomic number is 1 So hydrogen has 1 proton Ex: Carbon’s atomic number is 6 So carbon has 6 protons **The number of protons identifies the atom. Ex. 2 protons = He, 29 protons = Cu Point out these numbers on a periodic table in the room or have students access the periodic table in the textbook (pages 132-133 or near the back cover).

Think Pair Share With your partner, find the atomic number of each element: Carbon (C) Potassium (K) Beryllium (Be) Helium (He)

How do we know the number of subatomic particles in an atom? Mass number: the number of protons and neutrons in the nucleus Ex: Silicon can have a mass of 28. Since it has 14 proton it must have 14 neutrons # of neutrons = mass # - atomic #

Determining the number of protons and neutrons Li has a mass number of 7 and an atomic number of 3 Protons = 3 (same as atomic #) Neutrons= 7-3 = 4 (mass # - atomic #) Ne has a mass number of 20 and an atomic number of 10 Protons = 10 Neutrons = 20 - 10= 10

Try this example on your own!: Let’s check out Calcium (Ca)! 20 Calcium’s Atomic Number = Calcium’s Atomic Mass = 40 20 Calcium’s Neutrons =

Think Pair Share Decide how many protons and neutrons each element has. Carbon (C) Iodine (I) Silicon (Si) Iron (Fe)

What about the electrons? The electrons are equal to the number of protons So e- = p+ = atomic # Ex: Li has a mass # of 7 and an atomic # of 3 p+ = 3 no = 4 e- =3 Easy peasy lemon squeezy!… 

Think Ink Share Write your answers to the following and then share with your partner. How many electrons does Mercury (Hg) have? Barium (Ba)? Titanium (Ti)?

Determine the number of subatomic particles (all 3) in the following: Examples: 1. Find Chlorine (Cl) Cl has a mass # of 35 and an atomic # of 17 p+ = 17, no = 18, e- = 17 K has a mass # of 39 and an atomic # of 19 p+ = 19, no = 20 e- = 19

Think Ink Share Write your answers and then share with your partner. Find the number of protons, neutrons and electrons of the following: Titanium (Ti) Nickel (Ni) Copper (Cu)

How exactly are the particles arranged? Bohr Model of the atom: All of the protons and the neutrons The 3rd ring can hold up to 18 e- The 1st ring can hold up to 2 e- In this class we’ll focus on elements 1-18, so the third energy level will only have up to 8 electrons shown. Show pairs of e The 2nd ring can hold up to 8 e-

What does carbon look like? Mass # = 12 atomic # = 6 p+ = 6 no = 6 e- = 6 6 p and 6 n exist in the nucleus

Review of Atomic Structure Have students supply the missing names for each part of the atom. (Electron, nucleus, proton, and neutron).

Draw a Bohr Model of Sodium Protons (+) Neutrons (0) Electrons (-) In a neutral atom the number of protons (+) equals the number of electrons (-). How would the atom change if it gained an electron? Draw a Bohr model of sodium. Point out how the number of protons and neutrons are equal by filling out the data table. Ask students what would happen if the sodium atom were to gain an electron. Add another electron to the model and fill out the data table again to demonstrate that the number of protons remains constant.

Valence electrons – electrons in the outer energy level of an atom. The most stable atoms have a full outer energy level. For most elements, this is an octet. Octet – having eight valence electrons Neon One way to show the valence electrons of an atom is by using an Electron Dot Diagram. Explain that the electron dot diagram shows up to eight valence electrons. Each side of the symbol will receive one electron (dot) before any of the sides will have electron pairs.

Atoms will gain or lose valence electrons to become more stable. Ion – an atom that has gained or lost valence electrons. Use the lithium model to show how easily this atom can lose its outer electron to have a full energy level. Draw in another electron for fluorine to show how it will gain an electron to have an octet.

Positively charged due to losing electrons. Cations are named by simply adding “ion” to the name of the atom. Cation (cat-eye-on) Positively charged due to losing electrons. Explain that losing an electron, which is negatively charged, leaves more positive protons than electrons. This makes the cation positively charged. Lithium Ion

Forming Cations Use this slide to illustrate how removing electrons creates a positive charge.

Negatively charged due to gaining electrons. Anion (an-eye-on) Negatively charged due to gaining electrons. Fluoride Ion Anions are named by changing the end of the element name to –ide and add “ion.” Gaining electrons means gaining more negative charges. When negative electrons outnumber positive protons, the anion is negatively charged.

Forming Anions Use this slide to illustrate the way adding electrons changes the charge of the ion.

Vocabulary Builders (due Tues) Write a learning sentence and draw a picture to illustrate the following vocabulary terms: Valence electrons Octet Ion Cation Anion