Atoms & Periodic Table

Atoms &

The Periodic Table

Review & Brain Dump

Atomic Structure

• Nucleus (inside)

• Electron Cloud (outside)

Nucleus

Contains protons & neutrons

*ALL the mass is located in nucleus

*The charge of the nucleus is positive

Protons

• Positive Charge

• Same mass (size) as neutrons (bigger than electrons)

• Tells us the IDENTITY of the element

• Equal to the Atomic Number

• Equal to the total electrons

  (APE)

• Mass Number = P + N

  (MAN)

Neutrons

• Neutral Charge

• Same mass (size) as protons (bigger than electrons)

• Mass Number - P = N

  (MAN)

  *We cannot find neutrons on the periodic table! We must solve for it using M.A.N.

Multiple Choice

Which statement correctly describes the nucleus of an atom?

• The nucleus is negatively charged and contains no mass of the atom

• The nucleus is negatively charged and contains all the mass of the atom

• The nucleus is positively charged and contains all the mass of the atom

• The nucleus is positively charged and contains no mass of the atom

Multiple Choice

Atoms of which two elements have a combined total of 17 protons?

• Chlorine, Cl, and Hydrogen, H

• Neon, Ne, and Carbon, C

• Aluminum, Al, and Beryllium, Be

• Chlorine, Cl, and Helium, He

Electron Cloud

Contains electrons

*Energy levels = period number

*Negatively charged

Electrons

• Negative Charge

• Small (no mass)

• Total electrons = number of protons (APE)

• Valence electrons = group number (reactivity)

  *outer most electrons

Multiple Choice

The diagram shows a model of an atom. The model has four different symbols on it. Each symbol represents a different role for one of the particles within the atom. In this model, which particle determines the reactivity of this atom?

• Particle W

• Particle X

• Particle Y

• Particle Z

Multiple Choice

The diagram shows a model of an atom. Which element could this model represent?

• Carbon

• Oxygen

• Sulfur

• Fluorine

Periodic Table

• Groups & Periods

• Metals, Metalloids, Nonmetals

Groups

• Up and down

• Group numbers tell us the number of valence electrons (Group 17 = 7 valence electrons)

• Elements in the same group have similar reactivities

Reactive Groups

• Group 1: most reactive metals (1 valence electron)

• Group 17 (7A): most reactive nonmetals (7 valence electrons)

• Group 18 (8A): Nobel Gases--- least reactive, most stable, inert (8 valence electrons)

Periods

• Horizontal (side-to-side)

• Period number tells us the number of energy levels (rings) in an atom

Multiple Choice

Of the following atomic models, which represents the most reactive atom?

• A

• B

• C

• D

Multiple Choice

Which two elements have the same number of energy levels?

• S and Se

• Si and Sb

• Cu and Zn

• Ar and Kr

Metals

• Luster (shiny)

• Malleable (bends)

• Good conductor (moves heat & electricity)

Metalloids

• Luster (shiny)

• Brittle (breaks)

• Semi-conductor (kind of moves heat & electricity)

Nonmetals

• Dull (not shiny)

• Brittle (breaks)

• Insulators (does not move heat & electricity)

Multiple Choice

The periodic table is organized into groups and periods of elements. The characteristics of a certain group of elements are listed below. Which of these elements is in this group?

• Lithium

• Strontium

• Aluminum

• Silicon