Chemistry Chapter 4 Test

An atom has 10 protons, 15 neutrons and 10 electrons what is its mass number.

25

Copper occurs naturally as Cu-63 and Cu-65. Which isotope is more abundant?

Cu-63

The first person to ever talk about an atom was

Democritus

Atom 1- Protons=17 Neutrons=19 Atom 2- Atomic #= 18 Mass= 40 Electrons=18 Are these atoms isotopes of each other or different elements?

Different Elements - Cl & Ar

This particle determines what element you have - the elements identity.

Proton

Which particle has a positive charge?

Proton

A helium nucleus with two protons and two neutrons is called a(n) ____.

alpha particle

a high-speed electron with a 1- charge that is emitted during radioactive decay

beta particle

J.J. Thomson provided evidence that an atom...

contains negatively charged particles

What quantities vary between isotopes of an element?

neutrons and atomic mass

The majority of an atom's mass exists where?

nucleus

The particles of the atom you can find by knowing the atomic number.

protons and electrons

Rutherford's gold foil experiment provided evidence that...

there is a dense positively charged nucleus at the center of an atom.

24.1% of all the isotopes of a an element have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu. The atomic mass is 74.92 amu.How many protons does this element have?

33

(^7-3Li) has _______ neutrons

4

How many neutrons does the isotope of lithium have (^8_3Li)?

5

24.1% of all the isotopes of a an element have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu. What is the average mass of this element?

74.92

How many neutrons are in C-14?

8

How did Rutherford discover the proton?

Gold foil experiment

What contribution did John Dalton make to atomic theory?

He discovered that atoms were real

If X is the symbol for an element, which of the following two symbols represent isotopes of the same element? I. 7735X II. 7733X III. 8137X IV. 8135 X

I and IV

An element has three different isotopes. One has a mass of 35.00 amu; another has a mass of 36.00 amu; and another has a mass of 38.00 amu. What is the average atomic mass of this element?

Impossible to tell

What scientist is best known for his "Plum Pudding" (or "chocolate chip cookie") model of the atom?

J.J. Tomson

An atom's overall charge is ________.

Neutral

Choose the particle that has no charge.

Neutron

True or False: The majority of an atom is made up of empty space

True

An electron has a _____ charge.

negative