2. Atoms & Elements

The prefix eka- comes from the Sanskrit word for 'one.' Mendeleev used this prefix to indicate that the unknown element was one place away from the known element that followed the prefix. For example, eka-silicon, which we now call germanium, is one element below silicon. Mendeleev also predicted the existence of eka-manganese, which was not experimentally confirmed until 1937 because this element is radioactive and does not occur in nature. Based on the periodic table shown in Figure 7.1, what do we now call the element Mendeleev called eka-manganese?

Give the chemical symbol or name for the following elements, as appropriate: (c) cobalt

Give the chemical symbol or name for each of the following elements, as appropriate: (a) rhenium

What is the atomic number of the blue element?

The element indicated on the following periodic table is used in smoke detectors. Identify it, give its atomic number, and tell what kind of group it's in.

For each of the following elements, write its chemical symbol, locate it in the periodic table, give its atomic number, and indicate whether it is a metal, metalloid, or nonmetal: (g) sulphur.

How many elements are presently known? About how many occur naturally?

Look at the alphabetical list of elements inside the front cover. What are the symbols for the following elements? (a) Gadolinium (used in color TV screens) (b) Germanium (used in semiconductors) (c) Technetium (used in biomedical imaging) (d) Arsenic (used in pesticides)

Look at the alphabetical list of elements inside the front cover. What are the symbols for the following elements? (a) Cadmium (used in rechargeable Ni-cad batteries) (b) Iridium (used for hardening alloys) (c) Beryllium (used in the space shuttle) (d) Tungsten (used in light bulbs)

Look at the alphabetical list of elements inside the front cover. Give the names corresponding to the following symbols: (a) Te (b) Re (c) Be (d) Ar (e) Pu

Look at the alphabetical list of elements inside the front cover. Give the names corresponding to the following symbols: (a) B (b) Rh (c) Cf (d) Os (e) Ga

What is wrong with each of the following statements? (a) The symbol for tin is Ti. (b) The symbol for manganese is Mg. (c) The symbol for potassium is Po. (d) The symbol for helium is HE.

What is wrong with each of the following statements? (a) The symbol for carbon is ca. (b) The symbol for sodium is So. (c) The symbol for nitrogen is Ni. (d) The symbol for chlorine is Cr

Examine Figure 2.2, A portion of Mendeleev's periodic table. How was Mendeleev able to predict with a high level of accuracy the properties of the undiscovered elements beneath Al and Si in the periodic table?

Examine Figure 2.2, A portion of Mendeleev's periodic table. (a) Which characteristic was used to organize the elements in the table?

Examine Figure 2.3, The periodic table. (g) What is the symbol for the element located in period 3, group 4A?

In which of the periodic groups 1A, 2A, 5A, and 7A is the first letter of all elements' symbol the same as the first letter of their name?

Consider the stable elements through lead 1Z = 822. In how many instances are the atomic weights of the elements out of order relative to the atomic numbers of the elements?

The subscript giving the atomic number of an atom is often left off when writing an isotope symbol. For example, 6 often written simply as 13C. Why is this allowed?

Give the names and symbols for the following elements: (a) An element with atomic number 6 (b) An element with 18 protons in its nucleus (c) An element with 23 electrons