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Flashcards in 2 Atomic Structure Deck (13)
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1

what is a nucleus?

A nucleus is a small region in the center of an atom containing protons and neutrons.

2

What is an atomic number?

The number of protons in an atom is called atomic number or proton number?

3

What particle has a smallest mass?

Electron.

4

What is a shell?

The electrons are found at consiberable distances from the nucleus in a series of levels called energy levels or shells.

5

What is the charge of:
a) Electron
b) Proton
c) Neutron

a) -1
b) +1
c) 0

6

What is the relativ mass of:
a) Electron
b) Proton
c) Neutron

a) 0
b) 1
c) 1

7

What is the mass number?

The total number of protons and electrons in the nucleus.

8

Use the periodic table to find following numbers for the element cobalt Co:
a) the atomic number
b) the mass number
c) number of electrons
d) number of protons
e) number of neutrons

a) 27
b) 59
c) 27
d) 27
e) 32

9

What is the octet rule?

Atoms from the main group elements tend to reach full outer shells (to reach the electronic configuration of the nearest noble gas).

10

Write the electronic configuration of following atoms:

Lithium
Fluorine
Calcium
Nitrogen

Li - 2 , 1
F - 2 , 7
Ca - 2 , 8 , 8 , 2
N - 2 , 5

11

What is the definition for an isotope?

Atoms which have the same number of protons (and electrons) but different number of neutrons are called isotopes.

12

What is the relative atomic mass?

The ratio of the average mass of all isotopes is called relative atomic mass.

13

The element chlorine has two isotopes. The isotope Cl-35 is more often (75%) than the isotop Cl-37 (25%). Calculate the relative atomic mass.

(35*75+37*25)/2 * 100% = 35.5