Question

1. examine the elements listed below and identify the one element that is from a different periodic table group than the others.

a) sn
b) si
c) ti
d) ge

1. which statement below accurately describes the contributions of thompson?

a) created the modern periodic table
b) proposed the modern atomic theory
c) discovered the existence of electrons
d) ancient greek philosopher who proposed that matter was continuous

1. an isotope represented as s - 34

a) is an isotope of sodium.
b) must have exactly 18 electrons.
c) contains exactly 18 neutrons.
d) has 34 protons.

1. which of the following is not part of daltons atomic theory?

a) most of the atoms mass and all of its positive charge is contained in a small core called the nucleus.
b) each element is composed of tiny indestructible particles called atoms.
c) atoms combine in simple, whole - number ratios to form compounds.
d) all atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements.

1. which statement below accurately describes the contributions of dalton?

a) proposed the modern atomic theory
b) ancient greek philosopher who proposed that matter was continuous
c) discovered the existence of electrons
d) created the modern periodic table

1. an atom of a carbon - 14 isotope would contain

a) 8 protons, 6 neutrons, and 8 electrons.
b) 20 protons, 6 neutrons, and 20 electrons.
c) 14 protons, 6 neutrons, and 6 electrons.
d) 6 protons, 8 neutrons, and 8 electrons.
e) 6 protons, 8 neutrons, and 6 electrons.

1. which of the following elements has only 12 protons?

a) c
b) mg
c) o
d) zn

Explanation:

• Question 32: Sn (tin), Si (silicon), and Ge (germanium) are in group 14 of the periodic table. Ti (titanium) is in group 4.
• Question 33: Thompson discovered electrons. Mendeleev created the modern periodic table. Dalton proposed the modern atomic theory. Ancient Greek philosophers like Anaxagoras proposed continuous matter.
• Question 34: S - 34 is sulfur - 34. Sulfur has atomic number 16 (16 protons). For a neutral atom, electrons = protons = 16. Neutrons = mass number - atomic number = 34 - 16 = 18.
• Question 35: Dalton's atomic theory does not mention the nucleus. Rutherford's model introduced the nucleus.
• Question 36: Dalton proposed the modern atomic theory.
• Question 37: Carbon has atomic number 6 (6 protons). For a neutral atom, electrons = protons = 6. Neutrons = mass number - atomic number = 14 - 6 = 8.
• Question 38: Magnesium (Mg) has atomic number 12 (12 protons). Carbon (C) has 6 protons, oxygen (O) has 8 protons, and zinc (Zn) has 30 protons.

Answer:

1. c) Ti
2. c) discovered the existence of electrons
3. c) contains exactly 18 neutrons
4. a) Most of the atom's mass and all of its positive charge is contained in a small core called the nucleus
5. a) proposed the modern Atomic Theory
6. e) 6 protons, 8 neutrons, and 6 electrons
7. b) Mg